Merge pull request #9 from nden/refactor-and-tests

restructure and add stwcs tests

55 files changed, 0 insertions, 10634 deletions

diff --git a/lib/stwcs/__init__.py b/lib/stwcs/__init__.py
deleted file mode 100644
index 9f12bce..0000000
--- a/lib/stwcs/__init__.py
+++ /dev/null
@@ -1,33 +0,0 @@
-""" STWCS
-
-This package provides support for WCS based distortion models and coordinate
-transformation. It relies on PyWCS (based on WCSLIB). It consists of two
-subpackages:  updatewcs and wcsutil.
-
-updatewcs performs corrections to the
-basic WCS and includes other distortion infomation in the science files as
-header keywords or file extensions.
-
-Wcsutil provides an HSTWCS object which extends pywcs.WCS object and provides
-HST instrument specific information as well as methods for coordinate
-transformation. wcsutil also provides functions for manipulating alternate WCS
-descriptions in the headers.
-
-"""
-from __future__ import absolute_import, print_function # confidence high
-import os
-
-from . import distortion
-from stsci.tools import fileutil
-from stsci.tools import teal
-
-__docformat__ = 'restructuredtext'
-
-from .version import *
-
-try:
-    from . import gui
-    teal.print_tasknames(gui.__name__, os.path.dirname(gui.__file__))
-    print('\n')
-except:
-    print('No TEAL-based tasks available for this package!')
diff --git a/lib/stwcs/distortion/__init__.py b/lib/stwcs/distortion/__init__.py
deleted file mode 100644
index e69de29..0000000
--- a/lib/stwcs/distortion/__init__.py
+++ /dev/null
diff --git a/lib/stwcs/distortion/coeff_converter.py b/lib/stwcs/distortion/coeff_converter.py
deleted file mode 100644
index 415b512..0000000
--- a/lib/stwcs/distortion/coeff_converter.py
+++ /dev/null
@@ -1,142 +0,0 @@
-from __future__ import division, print_function # confidence high
-
-import numpy as np
-from astropy.io import fits
-from astropy import wcs as pywcs
-
-def sip2idc(wcs):
-    """
-    Converts SIP style coefficients to IDCTAB coefficients.
-
-    Parameters
-    ----------
-    wcs : `astropy.io.fits.Header` or `astropy.wcs.WCS` object
-    """
-    if isinstance(wcs, fits.Header):
-        ocx10 = wcs.get('OCX10', None)
-        ocx11 = wcs.get('OCX11', None)
-        ocy10 = wcs.get('OCY10', None)
-        ocy11 = wcs.get('OCY11', None)
-        order = wcs.get('A_ORDER', None)
-        sipa, sipb = _read_sip_kw(wcs)
-        if None in [ocx10, ocx11, ocy10, ocy11, sipa, sipb]:
-            print('Cannot convert SIP to IDC coefficients.\n')
-            return None, None
-    elif isinstance(wcs, pywcs.WCS):
-        try:
-            ocx10 = wcs.ocx10
-            ocx11 = wcs.ocx11
-            ocy10 = wcs.ocy10
-            ocy11 = wcs.ocy11
-        except AttributeError:
-            print('First order IDCTAB coefficients are not available.\n')
-            print('Cannot convert SIP to IDC coefficients.\n')
-            return None, None
-        try:
-            sipa = wcs.sip.a
-            sipb = wcs.sip.b
-        except AttributeError:
-            print('SIP coefficients are not available.')
-            print('Cannot convert SIP to IDC coefficients.\n')
-            return None, None
-        try:
-            order = wcs.sip.a_order
-        except AttributeError:
-            print('SIP model order unknown, exiting ...\n')
-            return None, None
-
-    else:
-        print('Input to sip2idc must be a PyFITS header or a wcsutil.HSTWCS object\n')
-        return
-
-
-    if None in [ocx10, ocx11, ocy10, ocy11]:
-        print('First order IDC coefficients not found, exiting ...\n')
-        return None, None
-    idc_coeff = np.array([[ocx11, ocx10], [ocy11, ocy10]])
-    cx = np.zeros((order+1,order+1), dtype=np.double)
-    cy = np.zeros((order+1,order+1), dtype=np.double)
-    for n in range(order+1):
-        for m in range(order+1):
-            if n >= m and n>=2:
-                sipval = np.array([[sipa[m,n-m]],[sipb[m,n-m]]])
-                idcval = np.dot(idc_coeff, sipval)
-                cx[n,m] = idcval[0]
-                cy[n,m] = idcval[1]
-
-    cx[1,0] = ocx10
-    cx[1,1] = ocx11
-    cy[1,0] = ocy10
-    cy[1,1] = ocy11
-
-    return cx, cy
-
-def _read_sip_kw(header):
-    """
-    Reads SIP header keywords and returns an array of coefficients.
-
-    If no SIP header keywords are found, None is returned.
-    """
-    if "A_ORDER" in header:
-        if "B_ORDER" not in header:
-            raise ValueError(
-                "A_ORDER provided without corresponding B_ORDER "
-                "keyword for SIP distortion")
-
-        m = int(header["A_ORDER"])
-        a = np.zeros((m+1, m+1), np.double)
-        for i in range(m+1):
-            for j in range(m-i+1):
-                a[i, j] = header.get("A_%d_%d" % (i, j), 0.0)
-
-        m = int(header["B_ORDER"])
-        b = np.zeros((m+1, m+1), np.double)
-        for i in range(m+1):
-            for j in range(m-i+1):
-                b[i, j] = header.get("B_%d_%d" % (i, j), 0.0)
-    elif "B_ORDER" in header:
-        raise ValueError(
-            "B_ORDER provided without corresponding A_ORDER "
-            "keyword for SIP distortion")
-    else:
-        a = None
-        b = None
-
-    return a , b
-
-
-"""
-def idc2sip(wcsobj, idctab = None):
-    if isinstance(wcs,pywcs.WCS):
-        try:
-            cx10 = wcsobj.ocx10
-            cx11 = wcsobj.cx11
-            cy10 = wcsobj.cy10
-            cy11 = wcsobj.cy11
-        except AttributeError:
-            print
-        try:
-            order = wcs.sip.a_order
-        except AttributeError:
-            print 'SIP model order unknown, exiting ...\n'
-            return
-    else:
-        print 'Input to sip2idc must be a PyFITS header or a wcsutil.HSTWCS object\n'
-        return
-
-    if None in [ocx10, ocx11, ocy10, ocy11]:
-        print 'First order IDC coefficients not found, exiting ...\n'
-        return
-    idc_coeff = np.array([[wcsobj.cx11, wcsobj.cx10], [wcsobj.cy11, wcsobj.cy10]])
-    cx = numpy.zeros((order+1,order+1), dtype=numpy.double)
-    cy = numpy.zeros((order+1,order+1), dtype=numpy.double)
-    for n in range(order+1):
-        for m in range(order+1):
-            if n >= m and n>=2:
-                sipval = numpy.array([[wcsobj.sip.a[n,m]],[wcsobj.sip.b[n,m]]])
-                idcval = numpy.dot(idc_coeff, sipval)
-                cx[m,n-m] = idcval[0]
-                cy[m,n-m] = idcval[1]
-
-    return cx, cy
-"""
diff --git a/lib/stwcs/distortion/models.py b/lib/stwcs/distortion/models.py
deleted file mode 100644
index 231a9f1..0000000
--- a/lib/stwcs/distortion/models.py
+++ /dev/null
@@ -1,362 +0,0 @@
-from __future__ import absolute_import, division, print_function # confidence high
-
-
-import numpy as np
-
-# Import PyDrizzle utility modules
-from . import mutil
-from .mutil import combin
-
-yes = True
-no = False
-
-#################
-#
-#
-#               Geometry/Distortion Classes
-#
-#
-#################
-
-class GeometryModel:
-    """
-    Base class for Distortion model.
-    There will be a separate class for each type of
-    model/filetype used with drizzle, i.e., IDCModel and
-    DrizzleModel.
-
-    Each class will know how to apply the distortion to a
-    single point and how to convert coefficients to an input table
-    suitable for the drizzle task.
-
-    Coefficients will be stored in CX,CY arrays.
-    """
-    #
-    #
-    #
-    #
-    #
-    #
-    #
-    NORDER = 3
-
-    def __init__(self):
-        "  This will open the given file and determine its type and norder."
-
-        #       Method to read in coefficients from given table and
-        #       populate the n arrays 'cx' and 'cy'.
-        #       This will be different for each type of input file,
-        #       IDCTAB vs. drizzle table.
-
-        # Set these up here for all sub-classes to use...
-        # But, calculate norder and cx,cy arrays in detector specific classes.
-        self.cx = None
-        self.cy = None
-        self.refpix = None
-        self.norder = self.NORDER
-        # Keep track of computed zero-point for distortion coeffs
-        self.x0 = None
-        self.y0 = None
-
-        # default values for these attributes
-        self.direction = 'forward'
-
-        self.pscale = 1.0
-
-    def shift(self, xs, ys):
-        """
-        Shift reference position of coefficients to new center
-        where (xs,ys) = old-reference-position - subarray/image center.
-        This will support creating coeffs files for drizzle which will
-        be applied relative to the center of the image, rather than relative
-        to the reference position of the chip.
-        """
-
-        _cxs = np.zeros(shape=self.cx.shape,dtype=self.cx.dtype)
-        _cys = np.zeros(shape=self.cy.shape,dtype=self.cy.dtype)
-        _k = self.norder + 1
-        # loop over each input coefficient
-        for m in range(_k):
-            for n in range(_k):
-                if m >= n:
-                    # For this coefficient, shift by xs/ys.
-                    _ilist = list(range(m, _k))
-                    # sum from m to k
-                    for i in _ilist:
-                        _jlist = list(range(n, i - (m-n)+1))
-                        # sum from n to i-(m-n)
-                        for j in _jlist:
-                            _cxs[m,n] += self.cx[i,j]*combin(j,n)*combin((i-j),(m-n))*pow(xs,(j-n))*pow(ys,((i-j)-(m-n)))
-                            _cys[m,n] += self.cy[i,j]*combin(j,n)*combin((i-j),(m-n))*pow(xs,(j-n))*pow(ys,((i-j)-(m-n)))
-        self.cx = _cxs.copy()
-        self.cy = _cys.copy()
-
-    def convert(self, tmpname, xref=None,yref=None,delta=yes):
-        """
-         Open up an ASCII file, output coefficients in drizzle
-          format after converting them as necessary.
-        First, normalize these coefficients to what drizzle expects
-        Normalize the coefficients by the MODEL/output plate scale.
-
-        16-May-2002:
-        Revised to work with higher order polynomials by John Blakeslee.
-        27-June-2002:
-            Added ability to shift coefficients to new center for support
-                of subarrays.
-        """
-        cx = self.cx/self.pscale
-        cy = self.cy/self.pscale
-        x0 = self.refpix['XDELTA'] + cx[0,0]
-        y0 = self.refpix['YDELTA'] + cy[0,0]
-        #xr = self.refpix['XREF']
-        #yr = self.refpix['YREF']
-        xr = self.refpix['CHIP_XREF']
-        yr = self.refpix['CHIP_YREF']
-
-
-
-        '''
-        if xref != None:
-            # Shift coefficients for use with drizzle
-            _xs = xref - self.refpix['XREF'] + 1.0
-            _ys = yref - self.refpix['YREF'] + 1.0
-
-
-            if _xs != 0 or _ys != 0:
-                cxs,cys= self.shift(cx, cy, _xs, _ys)
-                cx = cxs
-                cy = cys
-
-                # We only want to apply this shift to coeffs
-                # for subarray images.
-                if delta == no:
-                    cxs[0,0] = cxs[0,0] - _xs
-                    cys[0,0] = cys[0,0] - _ys
-
-                # Now, apply only the difference introduced by the distortion..
-                # i.e., (undistorted - original) shift.
-                x0 += cxs[0,0]
-                y0 += cys[0,0]
-        '''
-        self.x0 = x0 #+ 1.0
-        self.y0 = y0 #+ 1.0
-
-        # Now, write out the coefficients into an ASCII
-        # file in 'drizzle' format.
-        lines = []
-
-
-        lines.append('# Polynomial distortion coefficients\n')
-        lines.append('# Extracted from "%s" \n'%self.name)
-        lines.append('refpix %f %f \n'%(xr,yr))
-        if self.norder==3:
-            lines.append('cubic\n')
-        elif self.norder==4:
-            lines.append('quartic\n')
-        elif self.norder==5:
-            lines.append('quintic\n')
-        else:
-            raise ValueError("Drizzle cannot handle poly distortions of order %d" % self.norder)
-
-        str = '%16.8f %16.8g %16.8g %16.8g %16.8g \n'% (x0,cx[1,1],cx[1,0],cx[2,2],cx[2,1])
-        lines.append(str)
-        str = '%16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cx[2,0],cx[3,3],cx[3,2],cx[3,1],cx[3,0])
-        lines.append(str)
-        if self.norder>3:
-            str = '%16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cx[4,4],cx[4,3],cx[4,2],cx[4,1],cx[4,0])
-            lines.append(str)
-        if self.norder>4:
-            str = '%16.8g %16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cx[5,5],cx[5,4],cx[5,3],cx[5,2],cx[5,1],cx[5,0])
-            lines.append(str)
-        lines.append("\n")
-
-        str = '%16.8f %16.8g %16.8g %16.8g %16.8g \n'% (y0,cy[1,1],cy[1,0],cy[2,2],cy[2,1])
-        lines.append(str)
-        str = '%16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cy[2,0],cy[3,3],cy[3,2],cy[3,1],cy[3,0])
-        lines.append(str)
-        if self.norder>3:
-            str = '%16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cy[4,4],cy[4,3],cy[4,2],cy[4,1],cy[4,0])
-            lines.append(str)
-        if self.norder>4:
-            str = '%16.8g %16.8g %16.8g %16.8g %16.8g %16.8g \n'% (cy[5,5],cy[5,4],cy[5,3],cy[5,2],cy[5,1],cy[5,0])
-            lines.append(str)
-
-        output = open(tmpname,'w')
-        output.writelines(lines)
-        output.close()
-
-
-    def apply(self, pixpos,scale=1.0,order=None):
-        """
-         Apply coefficients to a pixel position or a list of positions.
-          This should be the same for all coefficients tables.
-        Return the geometrically-adjusted position
-        in arcseconds from the reference position as a tuple (x,y).
-
-        Compute delta from reference position
-        """
-        
-        """
-        scale actually is a ratio of pscale/self.model.pscale
-        what is pscale?
-        """
-        if self.cx == None:
-            return pixpos[:,0],pixpos[:,1]
-
-        if order is None:
-            order = self.norder
-
-        # Apply in the same way that 'drizzle' would...
-        _cx = self.cx / (self.pscale * scale)
-        _cy = self.cy / (self.pscale * scale)
-        _convert = no
-        _p = pixpos
-
-        # Do NOT include any zero-point terms in CX,CY here
-        # as they should not be scaled by plate-scale like rest
-        # of coeffs...  This makes the computations consistent
-        # with 'drizzle'.  WJH 17-Feb-2004
-        _cx[0,0] = 0.
-        _cy[0,0] = 0.
-
-        if isinstance(_p, list) or isinstance(_p, tuple):
-            _p = np.array(_p,dtype=np.float64)
-            _convert = yes
-
-        dxy = _p - (self.refpix['XREF'],self.refpix['YREF'])
-        # Apply coefficients from distortion model here...
-        c = _p * 0.
-        for i in range(order+1):
-            for j in range(i+1):
-                c[:,0] = c[:,0] + _cx[i][j] * pow(dxy[:,0],j) * pow(dxy[:,1],(i-j))
-                c[:,1] = c[:,1] + _cy[i][j] * pow(dxy[:,0],j) * pow(dxy[:,1],(i-j))
-        xc = c[:,0]
-        yc = c[:,1]
-
-        # Convert results back to same form as original input
-        if _convert:
-            xc = xc.tolist()
-            yc = yc.tolist()
-            # If a single tuple was input, return just a single tuple
-            if len(xc) == 1:
-                xc = xc[0]
-                yc = yc[0]
-
-        return xc,yc
-
-    def setPScaleCoeffs(self,pscale):
-        self.cx[1,1] = pscale
-        self.cy[1,0] = pscale
-
-        self.refpix['PSCALE'] = pscale
-        self.pscale = pscale
-
-
-class IDCModel(GeometryModel):
-    """
-    This class will open the IDCTAB, select proper row based on
-    chip/direction and populate cx,cy arrays.
-    We also need to read in SCALE, XCOM,YCOM, XREF,YREF as well.
-    """
-    def __init__(self, idcfile, date=None, chip=1, direction='forward',
-                filter1='CLEAR1',filter2='CLEAR2',offtab=None,  binned=1):
-        GeometryModel.__init__(self)
-        #
-        # Norder must be derived from the coeffs file itself,
-        # then the arrays can be setup. Thus, it needs to be
-        # done in the sub-class, not in the base class.
-        # Read in table.
-        # Populate cx,cy,scale, and other variables here.
-        #
-        self.name = idcfile
-        self.cx,self.cy,self.refpix,self.norder = mutil.readIDCtab(idcfile,
-                        chip=chip,direction=direction,filter1=filter1,filter2=filter2,
-                date=date, offtab=offtab)
-
-        if 'empty_model' in self.refpix and self.refpix['empty_model']:
-            pass
-        else:
-            self.refpix['PSCALE'] = self.refpix['PSCALE'] * binned
-            self.cx = self.cx * binned
-            self.cy = self.cy * binned
-            self.refpix['XREF'] = self.refpix['XREF'] / binned
-            self.refpix['YREF'] = self.refpix['YREF'] / binned
-            self.refpix['XSIZE'] = self.refpix['XSIZE'] / binned
-            self.refpix['YSIZE'] = self.refpix['YSIZE'] / binned
-
-        self.pscale = self.refpix['PSCALE']
-        
-
-class WCSModel(GeometryModel):
-    """
-    This class sets up a distortion model based on coefficients
-    found in the image header.
-    """
-    def __init__(self,header,rootname):
-        GeometryModel.__init__(self)
-
-
-        if 'rootname' in header:
-            self.name = header['rootname']
-        else:
-            self.name = rootname
-        # Initialize all necessary distortion arrays with
-        # default model...
-        #self.cx,self.cy,self.refpix,self.order = mutil.defaultModel()
-
-        # Read in values from header, and update distortion arrays.
-        self.cx,self.cy,self.refpix,self.norder = mutil.readWCSCoeffs(header)
-
-        self.pscale = self.refpix['PSCALE']
-
-
-
-class DrizzleModel(GeometryModel):
-    """
-    This class will read in an ASCII Cubic
-    drizzle coeffs file and populate the cx,cy arrays.
-    """
-
-    def __init__(self, idcfile, scale = None):
-        GeometryModel.__init__(self)
-        #
-        # We now need to read in the file, populate cx,cy, and
-        # other variables as necessary.
-        #
-        self.name = idcfile
-        self.cx,self.cy,self.refpix,self.norder = mutil.readCubicTable(idcfile)
-
-        # scale is the ratio wcs.pscale/model.pscale. 
-        # model.pscale for WFPC2 is passed from REFDATA.
-        # This is needed for WFPC2 binned data.
-        
-        if scale != None:
-            self.pscale = scale
-        else:
-            self.pscale = self.refpix['PSCALE']
-
-        """
-        The above definition looks wrong.
-        In one case it's a ratio in the other it's pscale.
-        
-        """
-
-class TraugerModel(GeometryModel):
-    """
-    This class will read in the ASCII Trauger coeffs
-    file, convert them to SIAF coefficients, then populate
-    the cx,cy arrays.
-    """
-    NORDER = 3
-
-    def __init__(self, idcfile,lam):
-        GeometryModel.__init__(self)
-        self.name = idcfile
-        self.cx,self.cy,self.refpix,self.norder = mutil.readTraugerTable(idcfile,lam)
-        self.pscale = self.refpix['PSCALE']
-        #
-        # Read in file here.
-        # Populate cx,cy, and other variables.
-        #
-
-
diff --git a/lib/stwcs/distortion/mutil.py b/lib/stwcs/distortion/mutil.py
deleted file mode 100644
index ed6a1ea..0000000
--- a/lib/stwcs/distortion/mutil.py
+++ /dev/null
@@ -1,703 +0,0 @@
-from __future__ import division, print_function # confidence high
-
-from stsci.tools import fileutil
-import numpy as np
-import calendar
-
-# Set up IRAF-compatible Boolean values
-yes = True
-no = False
-
-# This function read the IDC table and generates the two matrices with
-# the geometric correction coefficients.
-#
-#       INPUT: FITS object of open IDC table
-#       OUTPUT: coefficient matrices for Fx and Fy
-#
-#### If 'tabname' == None: This should return a default, undistorted
-####                        solution.
-#
-
-def readIDCtab (tabname, chip=1, date=None, direction='forward',
-                filter1=None,filter2=None, offtab=None):
-
-    """
-        Read IDCTAB, and optional OFFTAB if sepcified, and generate
-        the two matrices with the geometric correction coefficients.
-
-        If tabname == None, then return a default, undistorted solution.
-        If offtab is specified, dateobs also needs to be given.
-
-    """
-
- # Return a default geometry model if no IDCTAB filename
-    # is given.  This model will not distort the data in any way.
-    if tabname == None:
-        print('Warning: No IDCTAB specified! No distortion correction will be applied.')
-        return defaultModel()
-
-    # Implement default values for filters here to avoid the default
-    # being overwritten by values of None passed by user.
-    if filter1 == None or filter1.find('CLEAR') == 0 or filter1.strip() == '':
-        filter1 = 'CLEAR'
-    if filter2 == None or filter2.find('CLEAR') == 0 or filter2.strip() == '':
-        filter2 = 'CLEAR'
-
-    # Insure that tabname is full filename with fully expanded
-    # IRAF variables; i.e. 'jref$mc41442gj_idc.fits' should get
-    # expanded to '/data/cdbs7/jref/mc41442gj_idc.fits' before
-    # being used here.
-    # Open up IDC table now...
-    try:
-        ftab = fileutil.openImage(tabname)
-    except:
-        err_str =  "------------------------------------------------------------------------ \n"
-        err_str += "WARNING: the IDCTAB geometric distortion file specified in the image     \n"
-        err_str += "header was not found on disk. Please verify that your environment        \n"
-        err_str += "variable ('jref'/'uref'/'oref'/'nref') has been correctly defined. If    \n"
-        err_str += "you do not have the IDCTAB file, you may obtain the latest version       \n"
-        err_str += "of it from the relevant instrument page on the STScI HST website:        \n"
-        err_str += "http://www.stsci.edu/hst/ For WFPC2, STIS and NICMOS data, the           \n"
-        err_str += "present run will continue using the old coefficients provided in         \n"
-        err_str += "the Dither Package (ca. 1995-1998).                                      \n"
-        err_str += "------------------------------------------------------------------------ \n"
-        raise IOError(err_str)
-
-    #First thing we need, is to read in the coefficients from the IDC
-    # table and populate the Fx and Fy matrices.
-
-    if 'DETECTOR' in ftab['PRIMARY'].header:
-        detector = ftab['PRIMARY'].header['DETECTOR']
-    else:
-        if 'CAMERA' in ftab['PRIMARY'].header:
-            detector = str(ftab['PRIMARY'].header['CAMERA'])
-        else:
-            detector = 1
-    # First, read in TDD coeffs if present
-    phdr = ftab['PRIMARY'].header
-    instrument = phdr['INSTRUME']
-    if instrument == 'ACS' and detector == 'WFC':
-        skew_coeffs = read_tdd_coeffs(phdr, chip=chip)
-    else:
-        skew_coeffs = None
-
-    # Set default filters for SBC
-    if detector == 'SBC':
-        if filter1 == 'CLEAR':
-            filter1 = 'F115LP'
-            filter2 = 'N/A'
-        if filter2 == 'CLEAR':
-            filter2 = 'N/A'
-
-    # Read FITS header to determine order of fit, i.e. k
-    norder = ftab['PRIMARY'].header['NORDER']
-    if norder < 3:
-        order = 3
-    else:
-        order = norder
-
-    fx = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    fy = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-
-    #Determine row from which to get the coefficients.
-    # How many rows do we have in the table...
-    fshape = ftab[1].data.shape
-    colnames = ftab[1].data.names
-    row = -1
-
-    # Loop over all the rows looking for the one which corresponds
-    # to the value of CCDCHIP we are working on...
-    for i in range(fshape[0]):
-
-        try:
-            # Match FILTER combo to appropriate row,
-            #if there is a filter column in the IDCTAB...
-            if 'FILTER1' in colnames and 'FILTER2' in colnames:
-
-                filt1 = ftab[1].data.field('FILTER1')[i]
-                if filt1.find('CLEAR') > -1: filt1 = filt1[:5]
-
-                filt2 = ftab[1].data.field('FILTER2')[i]
-                if filt2.find('CLEAR') > -1: filt2 = filt2[:5]
-            else:
-                if 'OPT_ELEM' in colnames:
-                    filt1 = ftab[1].data.field('OPT_ELEM')
-                    if filt1.find('CLEAR') > -1: filt1 = filt1[:5]
-                else:
-                    filt1 = filter1
-
-                if 'FILTER' in colnames:
-                    _filt = ftab[1].data.field('FILTER')[i]
-                    if _filt.find('CLEAR') > -1: _filt = _filt[:5]
-                    if 'OPT_ELEM' in colnames:
-                        filt2 = _filt
-                    else:
-                        filt1 = _filt
-                        filt2 = 'CLEAR'
-                else:
-                    filt2 = filter2
-        except:
-            # Otherwise assume all rows apply and compare to input filters...
-            filt1 = filter1
-            filt2 = filter2
-
-        if 'DETCHIP' in colnames:
-            detchip = ftab[1].data.field('DETCHIP')[i]
-            if not str(detchip).isdigit():
-                detchip = 1
-        else:
-            detchip = 1
-
-        if 'DIRECTION' in colnames:
-            direct = ftab[1].data.field('DIRECTION')[i].lower().strip()
-        else:
-            direct = 'forward'
-
-        if filt1 == filter1.strip() and filt2 == filter2.strip():
-            if direct == direction.strip():
-                if int(detchip) == int(chip) or int(detchip) == -999:
-                    row = i
-                    break
-
-    joinstr = ','
-    if 'CLEAR' in filter1:
-        f1str = ''
-        joinstr = ''
-    else:
-        f1str = filter1.strip()
-    if 'CLEAR' in filter2:
-        f2str = ''
-        joinstr = ''
-    else:
-        f2str = filter2.strip()
-    filtstr = (joinstr.join([f1str,f2str])).strip()
-    if row < 0:
-        err_str = '\nProblem finding row in IDCTAB! Could not find row matching:\n'
-        err_str += '        CHIP: '+str(detchip)+'\n'
-        err_str += '     FILTERS: '+filtstr+'\n'
-        ftab.close()
-        del ftab
-        raise LookupError(err_str)
-    else:
-        print('- IDCTAB: Distortion model from row',str(row+1),'for chip',detchip,':',filtstr)
-
-    # Read in V2REF and V3REF: this can either come from current table,
-    # or from an OFFTAB if time-dependent (i.e., for WFPC2)
-    theta = None
-    if 'V2REF' in colnames:
-        v2ref = ftab[1].data.field('V2REF')[row]
-        v3ref = ftab[1].data.field('V3REF')[row]
-    else:
-        # Read V2REF/V3REF from offset table (OFFTAB)
-        if offtab:
-            v2ref,v3ref,theta = readOfftab(offtab, date, chip=detchip)
-        else:
-            v2ref = 0.0
-            v3ref = 0.0
-
-    if theta == None:
-        if 'THETA' in colnames:
-            theta = ftab[1].data.field('THETA')[row]
-        else:
-            theta = 0.0
-
-    refpix = {}
-    refpix['XREF'] = ftab[1].data.field('XREF')[row]
-    refpix['YREF'] = ftab[1].data.field('YREF')[row]
-    refpix['XSIZE'] = ftab[1].data.field('XSIZE')[row]
-    refpix['YSIZE'] = ftab[1].data.field('YSIZE')[row]
-    refpix['PSCALE'] = round(ftab[1].data.field('SCALE')[row],8)
-    refpix['V2REF'] = v2ref
-    refpix['V3REF'] = v3ref
-    refpix['THETA'] = theta
-    refpix['XDELTA'] = 0.0
-    refpix['YDELTA'] = 0.0
-    refpix['DEFAULT_SCALE'] = yes
-    refpix['centered'] = no
-    refpix['skew_coeffs'] = skew_coeffs
-    # Now that we know which row to look at, read coefficients into the
-    #   numeric arrays we have set up...
-    # Setup which column name convention the IDCTAB follows
-    # either: A,B or CX,CY
-    if 'CX10' in ftab[1].data.names:
-        cxstr = 'CX'
-        cystr = 'CY'
-    else:
-        cxstr = 'A'
-        cystr = 'B'
-
-    for i in range(norder+1):
-        if i > 0:
-            for j in range(i+1):
-                xcname = cxstr+str(i)+str(j)
-                ycname = cystr+str(i)+str(j)
-                fx[i,j] = ftab[1].data.field(xcname)[row]
-                fy[i,j] = ftab[1].data.field(ycname)[row]
-
-    ftab.close()
-    del ftab
-
-    # If CX11 is 1.0 and not equal to the PSCALE, then the
-    # coeffs need to be scaled
-
-    if fx[1,1] == 1.0 and abs(fx[1,1]) != refpix['PSCALE']:
-        fx *= refpix['PSCALE']
-        fy *= refpix['PSCALE']
-
-    # Return arrays and polynomial order read in from table.
-    # NOTE: XREF and YREF are stored in Fx,Fy arrays respectively.
-    return fx,fy,refpix,order
-#
-#
-# Time-dependent skew correction coefficients (only ACS/WFC)
-#
-#
-def read_tdd_coeffs(phdr, chip=1):
-    ''' Read in the TDD related keywords from the PRIMARY header of the IDCTAB
-    '''
-    # Insure we have an integer form of chip
-    ic = int(chip)
-
-    skew_coeffs = {}
-    skew_coeffs['TDDORDER'] = 0
-    skew_coeffs['TDD_DATE'] = ""
-    skew_coeffs['TDD_A'] = None
-    skew_coeffs['TDD_B'] = None
-    skew_coeffs['TDD_CY_BETA'] = None
-    skew_coeffs['TDD_CY_ALPHA'] = None
-    skew_coeffs['TDD_CX_BETA'] = None
-    skew_coeffs['TDD_CX_ALPHA'] = None
-
-    # Skew-based TDD coefficients
-    skew_terms = ['TDD_CTB','TDD_CTA','TDD_CYA','TDD_CYB','TDD_CXA','TDD_CXB']
-    for s in skew_terms:
-        skew_coeffs[s] = None
-
-    if "TDD_CTB1" in phdr:
-        # We have the 2015-calibrated TDD correction to apply
-        # This correction is based on correcting the skew in the linear terms
-        # not just set polynomial terms
-        print("Using 2015-calibrated VAFACTOR-corrected TDD correction...")
-        skew_coeffs['TDD_DATE'] = phdr['TDD_DATE']
-        for s in skew_terms:
-            skew_coeffs[s] = phdr.get('{0}{1}'.format(s,ic),None)
-
-    elif "TDD_CYB1" in phdr:
-        # We have 2014-calibrated TDD correction to apply, not J.A.-derived values
-        print("Using 2014-calibrated TDD correction...")
-        skew_coeffs['TDD_DATE'] = phdr['TDD_DATE']
-        # Read coefficients for TDD Y coefficient
-        cyb_kw = 'TDD_CYB{0}'.format(int(chip))
-        skew_coeffs['TDD_CY_BETA'] = phdr.get(cyb_kw,None)
-        cya_kw = 'TDD_CYA{0}'.format(int(chip))
-        tdd_cya = phdr.get(cya_kw,None)
-        if tdd_cya == 0 or tdd_cya == 'N/A': tdd_cya = None
-        skew_coeffs['TDD_CY_ALPHA'] = tdd_cya
-
-        # Read coefficients for TDD X coefficient
-        cxb_kw = 'TDD_CXB{0}'.format(int(chip))
-        skew_coeffs['TDD_CX_BETA'] = phdr.get(cxb_kw,None)
-        cxa_kw = 'TDD_CXA{0}'.format(int(chip))
-        tdd_cxa = phdr.get(cxa_kw,None)
-        if tdd_cxa == 0 or tdd_cxa == 'N/A': tdd_cxa = None
-        skew_coeffs['TDD_CX_ALPHA'] = tdd_cxa
-
-    else:
-        if "TDDORDER" in phdr:
-            n = int(phdr["TDDORDER"])
-        else:
-            print('TDDORDER kw not present, using default TDD correction')
-            return None
-
-        a = np.zeros((n+1,), np.float64)
-        b = np.zeros((n+1,), np.float64)
-        for i in range(n+1):
-            a[i] = phdr.get(("TDD_A%d" % i), 0.0)
-            b[i] = phdr.get(("TDD_B%d" % i), 0.0)
-        if (a==0).all() and (b==0).all():
-            print('Warning: TDD_A and TDD_B coeffiecients have values of 0, \n \
-                   but TDDORDER is %d.' % TDDORDER)
-
-        skew_coeffs['TDDORDER'] = n
-        skew_coeffs['TDD_DATE'] = phdr['TDD_DATE']
-        skew_coeffs['TDD_A'] = a
-        skew_coeffs['TDD_B'] = b
-
-    return skew_coeffs
-
-def readOfftab(offtab, date, chip=None):
-
-
-#Read V2REF,V3REF from a specified offset table (OFFTAB).
-# Return a default geometry model if no IDCTAB filenam  e
-# is given.  This model will not distort the data in any way.
-
-    if offtab == None:
-        return 0.,0.
-
-    # Provide a default value for chip
-    if chip:
-        detchip = chip
-    else:
-        detchip = 1
-
-    # Open up IDC table now...
-    try:
-        ftab = fileutil.openImage(offtab)
-    except:
-        raise IOError("Offset table '%s' not valid as specified!" % offtab)
-
-    #Determine row from which to get the coefficients.
-    # How many rows do we have in the table...
-    fshape = ftab[1].data.shape
-    colnames = ftab[1].data.names
-    row = -1
-
-    row_start = None
-    row_end = None
-
-    v2end = None
-    v3end = None
-    date_end = None
-    theta_end = None
-
-    num_date = convertDate(date)
-    # Loop over all the rows looking for the one which corresponds
-    # to the value of CCDCHIP we are working on...
-    for ri in range(fshape[0]):
-        i = fshape[0] - ri - 1
-        if 'DETCHIP' in colnames:
-            detchip = ftab[1].data.field('DETCHIP')[i]
-        else:
-            detchip = 1
-
-        obsdate = convertDate(ftab[1].data.field('OBSDATE')[i])
-
-        # If the row is appropriate for the chip...
-            # Interpolate between dates
-        if int(detchip) == int(chip) or int(detchip) == -999:
-            if num_date <= obsdate:
-                date_end = obsdate
-                v2end = ftab[1].data.field('V2REF')[i]
-                v3end = ftab[1].data.field('V3REF')[i]
-                theta_end = ftab[1].data.field('THETA')[i]
-                row_end = i
-                continue
-
-            if row_end == None and (num_date > obsdate):
-                date_end = obsdate
-                v2end = ftab[1].data.field('V2REF')[i]
-                v3end = ftab[1].data.field('V3REF')[i]
-                theta_end = ftab[1].data.field('THETA')[i]
-                row_end = i
-                continue
-
-            if num_date > obsdate:
-                date_start = obsdate
-                v2start = ftab[1].data.field('V2REF')[i]
-                v3start = ftab[1].data.field('V3REF')[i]
-                theta_start = ftab[1].data.field('THETA')[i]
-                row_start = i
-                break
-
-    ftab.close()
-    del ftab
-
-    if row_start == None and row_end == None:
-        print('Row corresponding to DETCHIP of ',detchip,' was not found!')
-        raise LookupError
-    elif row_start == None:
-        print('- OFFTAB: Offset defined by row',str(row_end+1))
-    else:
-        print('- OFFTAB: Offset interpolated from rows',str(row_start+1),'and',str(row_end+1))
-
-    # Now, do the interpolation for v2ref, v3ref, and theta
-    if row_start == None or row_end == row_start:
-        # We are processing an observation taken after the last calibration
-        date_start = date_end
-        v2start = v2end
-        v3start = v3end
-        _fraction = 0.
-        theta_start = theta_end
-    else:
-        _fraction = float((num_date - date_start)) / float((date_end - date_start))
-
-    v2ref = _fraction * (v2end - v2start) + v2start
-    v3ref = _fraction * (v3end - v3start) + v3start
-    theta = _fraction * (theta_end - theta_start) + theta_start
-
-    return v2ref,v3ref,theta
-
-def readWCSCoeffs(header):
-
-    #Read distortion coeffs from WCS header keywords and
-    #populate distortion coeffs arrays.
-
-    # Read in order for polynomials
-    _xorder = header['a_order']
-    _yorder = header['b_order']
-    order = max(max(_xorder,_yorder),3)
-
-    fx = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    fy = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-
-    # Read in CD matrix
-    _cd11 = header['cd1_1']
-    _cd12 = header['cd1_2']
-    _cd21 = header['cd2_1']
-    _cd22 = header['cd2_2']
-    _cdmat = np.array([[_cd11,_cd12],[_cd21,_cd22]])
-    _theta = np.arctan2(-_cd12,_cd22)
-    _rotmat = np.array([[np.cos(_theta),np.sin(_theta)],
-                      [-np.sin(_theta),np.cos(_theta)]])
-    _rCD = np.dot(_rotmat,_cdmat)
-    _skew = np.arcsin(-_rCD[1][0] / _rCD[0][0])
-    _scale = _rCD[0][0] * np.cos(_skew) * 3600.
-    _scale2 = _rCD[1][1] * 3600.
-
-    # Set up refpix
-    refpix = {}
-    refpix['XREF'] = header['crpix1']
-    refpix['YREF'] = header['crpix2']
-    refpix['XSIZE'] = header['naxis1']
-    refpix['YSIZE'] = header['naxis2']
-    refpix['PSCALE'] = _scale
-    refpix['V2REF'] = 0.
-    refpix['V3REF'] = 0.
-    refpix['THETA'] = np.rad2deg(_theta)
-    refpix['XDELTA'] = 0.0
-    refpix['YDELTA'] = 0.0
-    refpix['DEFAULT_SCALE'] = yes
-    refpix['centered'] = yes
-
-
-    # Set up template for coeffs keyword names
-    cxstr = 'A_'
-    cystr = 'B_'
-    # Read coeffs into their own matrix
-    for i in range(_xorder+1):
-        for j in range(i+1):
-            xcname = cxstr+str(j)+'_'+str(i-j)
-            if xcname in header:
-                fx[i,j] = header[xcname]
-
-    # Extract Y coeffs separately as a different order may
-    # have been used to fit it.
-    for i in range(_yorder+1):
-        for j in range(i+1):
-            ycname = cystr+str(j)+'_'+str(i-j)
-            if ycname in header:
-                fy[i,j] = header[ycname]
-
-    # Now set the linear terms
-    fx[0][0] = 1.0
-    fy[0][0] = 1.0
-
-    return fx,fy,refpix,order
-
-
-def readTraugerTable(idcfile,wavelength):
-
-    # Return a default geometry model if no coefficients filename
-    # is given.  This model will not distort the data in any way.
-    if idcfile == None:
-        return fileutil.defaultModel()
-
-    # Trauger coefficients only result in a cubic file...
-    order = 3
-    numco = 10
-    a_coeffs = [0] * numco
-    b_coeffs = [0] * numco
-    indx = _MgF2(wavelength)
-
-    ifile = open(idcfile,'r')
-    # Search for the first line of the coefficients
-    _line = fileutil.rAsciiLine(ifile)
-    while _line[:7].lower() != 'trauger':
-        _line = fileutil.rAsciiLine(ifile)
-    # Read in each row of coefficients,split them into their values,
-    # and convert them into cubic coefficients based on
-    # index of refraction value for the given wavelength
-    # Build X coefficients from first 10 rows of Trauger coefficients
-    j = 0
-    while j < 20:
-        _line = fileutil.rAsciiLine(ifile)
-        if _line == '': continue
-        _lc = _line.split()
-        if j < 10:
-            a_coeffs[j] = float(_lc[0])+float(_lc[1])*(indx-1.5)+float(_lc[2])*(indx-1.5)**2
-        else:
-            b_coeffs[j-10] = float(_lc[0])+float(_lc[1])*(indx-1.5)+float(_lc[2])*(indx-1.5)**2
-        j = j + 1
-
-    ifile.close()
-    del ifile
-
-    # Now, convert the coefficients into a Numeric array
-    # with the right coefficients in the right place.
-    # Populate output values now...
-    fx = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    fy = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    # Assign the coefficients to their array positions
-    fx[0,0] = 0.
-    fx[1] = np.array([a_coeffs[2],a_coeffs[1],0.,0.],dtype=np.float64)
-    fx[2] = np.array([a_coeffs[5],a_coeffs[4],a_coeffs[3],0.],dtype=np.float64)
-    fx[3] = np.array([a_coeffs[9],a_coeffs[8],a_coeffs[7],a_coeffs[6]],dtype=np.float64)
-    fy[0,0] = 0.
-    fy[1] = np.array([b_coeffs[2],b_coeffs[1],0.,0.],dtype=np.float64)
-    fy[2] = np.array([b_coeffs[5],b_coeffs[4],b_coeffs[3],0.],dtype=np.float64)
-    fy[3] = np.array([b_coeffs[9],b_coeffs[8],b_coeffs[7],b_coeffs[6]],dtype=np.float64)
-
-    # Used in Pattern.computeOffsets()
-    refpix = {}
-    refpix['XREF'] = None
-    refpix['YREF'] = None
-    refpix['V2REF'] = None
-    refpix['V3REF'] = None
-    refpix['XDELTA'] = 0.
-    refpix['YDELTA'] = 0.
-    refpix['PSCALE'] = None
-    refpix['DEFAULT_SCALE'] = no
-    refpix['centered'] = yes
-
-    return fx,fy,refpix,order
-
-
-def readCubicTable(idcfile):
-    # Assumption: this will only be used for cubic file...
-    order = 3
-    # Also, this function does NOT perform any scaling on
-    # the coefficients, it simply passes along what is found
-    # in the file as is...
-
-    # Return a default geometry model if no coefficients filename
-    # is given.  This model will not distort the data in any way.
-    if idcfile == None:
-        return fileutil.defaultModel()
-
-    ifile = open(idcfile,'r')
-    # Search for the first line of the coefficients
-    _line = fileutil.rAsciiLine(ifile)
-
-    _found = no
-    while _found == no:
-        if _line[:7] in  ['cubic','quartic','quintic'] or _line[:4] == 'poly':
-            found = yes
-            break
-        _line = fileutil.rAsciiLine(ifile)
-
-    # Read in each row of coefficients, without line breaks or newlines
-    # split them into their values, and create a list for A coefficients
-    # and another list for the B coefficients
-    _line = fileutil.rAsciiLine(ifile)
-    a_coeffs = _line.split()
-
-    x0 = float(a_coeffs[0])
-    _line = fileutil.rAsciiLine(ifile)
-    a_coeffs[len(a_coeffs):] = _line.split()
-    # Scale coefficients for use within PyDrizzle
-    for i in range(len(a_coeffs)):
-        a_coeffs[i] = float(a_coeffs[i])
-
-    _line = fileutil.rAsciiLine(ifile)
-    b_coeffs = _line.split()
-    y0 = float(b_coeffs[0])
-    _line = fileutil.rAsciiLine(ifile)
-    b_coeffs[len(b_coeffs):] = _line.split()
-    # Scale coefficients for use within PyDrizzle
-    for i in range(len(b_coeffs)):
-        b_coeffs[i] = float(b_coeffs[i])
-
-    ifile.close()
-    del ifile
-    # Now, convert the coefficients into a Numeric array
-    # with the right coefficients in the right place.
-    # Populate output values now...
-    fx = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    fy = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    # Assign the coefficients to their array positions
-    fx[0,0] = 0.
-    fx[1] = np.array([a_coeffs[2],a_coeffs[1],0.,0.],dtype=np.float64)
-    fx[2] = np.array([a_coeffs[5],a_coeffs[4],a_coeffs[3],0.],dtype=np.float64)
-    fx[3] = np.array([a_coeffs[9],a_coeffs[8],a_coeffs[7],a_coeffs[6]],dtype=np.float64)
-    fy[0,0] = 0.
-    fy[1] = np.array([b_coeffs[2],b_coeffs[1],0.,0.],dtype=np.float64)
-    fy[2] = np.array([b_coeffs[5],b_coeffs[4],b_coeffs[3],0.],dtype=np.float64)
-    fy[3] = np.array([b_coeffs[9],b_coeffs[8],b_coeffs[7],b_coeffs[6]],dtype=np.float64)
-
-    # Used in Pattern.computeOffsets()
-    refpix = {}
-    refpix['XREF'] = None
-    refpix['YREF'] = None
-    refpix['V2REF'] = x0
-    refpix['V3REF'] = y0
-    refpix['XDELTA'] = 0.
-    refpix['YDELTA'] = 0.
-    refpix['PSCALE'] = None
-    refpix['DEFAULT_SCALE'] = no
-    refpix['centered'] = yes
-
-    return fx,fy,refpix,order
-
-def factorial(n):
-    """ Compute a factorial for integer n. """
-    m = 1
-    for i in range(int(n)):
-        m = m * (i+1)
-    return m
-
-def combin(j,n):
-    """ Return the combinatorial factor for j in n."""
-    return (factorial(j) / (factorial(n) * factorial( (j-n) ) ) )
-
-
-def defaultModel():
-    """ This function returns a default, non-distorting model
-        that can be used with the data.
-    """
-    order = 3
-
-    fx = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-    fy = np.zeros(shape=(order+1,order+1),dtype=np.float64)
-
-    fx[1,1] = 1.
-    fy[1,0] = 1.
-
-    # Used in Pattern.computeOffsets()
-    refpix = {}
-    refpix['empty_model'] = yes
-    refpix['XREF'] = None
-    refpix['YREF'] = None
-    refpix['V2REF'] = 0.
-    refpix['XSIZE'] = 0.
-    refpix['YSIZE'] = 0.
-    refpix['V3REF'] = 0.
-    refpix['XDELTA'] = 0.
-    refpix['YDELTA'] = 0.
-    refpix['PSCALE'] = None
-    refpix['DEFAULT_SCALE'] = no
-    refpix['THETA'] = 0.
-    refpix['centered'] = yes
-    return fx,fy,refpix,order
-
-# Function to compute the index of refraction for MgF2 at
-# the specified wavelength for use with Trauger coefficients
-def _MgF2(lam):
-    _sig = pow((1.0e7/lam),2)
-    return np.sqrt(1.0 + 2.590355e10/(5.312993e10-_sig) +
-        4.4543708e9/(11.17083e9-_sig) + 4.0838897e5/(1.766361e5-_sig))
-
-
-def convertDate(date):
-    """ Converts the DATE-OBS date string into an integer of the
-        number of seconds since 1970.0 using calendar.timegm().
-
-        INPUT: DATE-OBS in format of 'YYYY-MM-DD'.
-        OUTPUT: Date (integer) in seconds.
-    """
-
-    _dates = date.split('-')
-    _val = 0
-    _date_tuple = (int(_dates[0]), int(_dates[1]), int(_dates[2]), 0, 0, 0, 0, 0, 0)
-
-    return calendar.timegm(_date_tuple)
diff --git a/lib/stwcs/distortion/utils.py b/lib/stwcs/distortion/utils.py
deleted file mode 100644
index 4228f62..0000000
--- a/lib/stwcs/distortion/utils.py
+++ /dev/null
@@ -1,270 +0,0 @@
-from __future__ import division, print_function # confidence high
-
-import os
-
-import numpy as np
-from numpy import linalg
-from astropy import wcs as pywcs
-
-from stwcs import wcsutil
-from stwcs import updatewcs
-from numpy import sqrt, arctan2
-from stsci.tools import fileutil
-
-def output_wcs(list_of_wcsobj, ref_wcs=None, owcs=None, undistort=True):
-    """
-    Create an output WCS.
-
-    Parameters
-    ----------
-    list_of_wcsobj: Python list
-                    a list of HSTWCS objects
-    ref_wcs: an HSTWCS object
-             to be used as a reference WCS, in case outwcs is None.
-             if ref_wcs is None (default), the first member of the list
-             is used as a reference
-    outwcs:  an HSTWCS object
-             the tangent plane defined by this object is used as a reference
-    undistort: boolean (default-True)
-              a flag whether to create an undistorted output WCS
-    """
-    fra_dec = np.vstack([w.calc_footprint() for w in list_of_wcsobj])
-    wcsname = list_of_wcsobj[0].wcs.name
-
-    # This new algorithm may not be strictly necessary, but it may be more
-    # robust in handling regions near the poles or at 0h RA.
-    crval1,crval2 = computeFootprintCenter(fra_dec)
-
-    crval = np.array([crval1,crval2], dtype=np.float64) # this value is now zero-based
-    if owcs is None:
-        if ref_wcs is None:
-            ref_wcs = list_of_wcsobj[0].deepcopy()
-        if undistort:
-            #outwcs = undistortWCS(ref_wcs)
-            outwcs = make_orthogonal_cd(ref_wcs)
-        else:
-            outwcs = ref_wcs.deepcopy()
-        outwcs.wcs.crval = crval
-        outwcs.wcs.set()
-        outwcs.pscale = sqrt(outwcs.wcs.cd[0,0]**2 + outwcs.wcs.cd[1,0]**2)*3600.
-        outwcs.orientat = arctan2(outwcs.wcs.cd[0,1],outwcs.wcs.cd[1,1]) * 180./np.pi
-    else:
-        outwcs = owcs.deepcopy()
-        outwcs.pscale = sqrt(outwcs.wcs.cd[0,0]**2 + outwcs.wcs.cd[1,0]**2)*3600.
-        outwcs.orientat = arctan2(outwcs.wcs.cd[0,1],outwcs.wcs.cd[1,1]) * 180./np.pi
-
-    tanpix = outwcs.wcs.s2p(fra_dec, 0)['pixcrd']
-
-    outwcs._naxis1 = int(np.ceil(tanpix[:,0].max() - tanpix[:,0].min()))
-    outwcs._naxis2 = int(np.ceil(tanpix[:,1].max() - tanpix[:,1].min()))
-    crpix = np.array([outwcs._naxis1/2., outwcs._naxis2/2.], dtype=np.float64)
-    outwcs.wcs.crpix = crpix
-    outwcs.wcs.set()
-    tanpix = outwcs.wcs.s2p(fra_dec, 0)['pixcrd']
-
-    # shift crpix to take into account (floating-point value of) position of
-    # corner pixel relative to output frame size: no rounding necessary...
-    newcrpix = np.array([crpix[0]+tanpix[:,0].min(), crpix[1]+
-                         tanpix[:,1].min()])
-
-    newcrval = outwcs.wcs.p2s([newcrpix], 1)['world'][0]
-    outwcs.wcs.crval = newcrval
-    outwcs.wcs.set()
-    outwcs.wcs.name = wcsname # keep track of label for this solution
-    return outwcs
-
-def computeFootprintCenter(edges):
-    """ Geographic midpoint in spherical coords for points defined by footprints.
-        Algorithm derived from: http://www.geomidpoint.com/calculation.html
-
-        This algorithm should be more robust against discontinuities at the poles.
-    """
-    alpha = np.deg2rad(edges[:,0])
-    dec = np.deg2rad(edges[:,1])
-
-    xmean = np.mean(np.cos(dec)*np.cos(alpha))
-    ymean = np.mean(np.cos(dec)*np.sin(alpha))
-    zmean = np.mean(np.sin(dec))
-
-    crval1 = np.rad2deg(np.arctan2(ymean,xmean))%360.0
-    crval2 = np.rad2deg(np.arctan2(zmean,np.sqrt(xmean*xmean+ymean*ymean)))
-
-    return crval1,crval2
-
-def make_orthogonal_cd(wcs):
-    """ Create a perfect (square, orthogonal, undistorted) CD matrix from the
-        input WCS.
-    """
-    # get determinant of the CD matrix:
-    cd = wcs.celestial.pixel_scale_matrix
-
-
-    if hasattr(wcs, 'idcv2ref') and wcs.idcv2ref is not None:
-        # Convert the PA_V3 orientation to the orientation at the aperture
-        # This is for the reference chip only - we use this for the
-        # reference tangent plane definition
-        # It has the same orientation as the reference chip
-        pv = updatewcs.makewcs.troll(wcs.pav3,wcs.wcs.crval[1],wcs.idcv2ref,wcs.idcv3ref)
-        # Add the chip rotation angle
-        if wcs.idctheta:
-            pv += wcs.idctheta
-        cs = np.cos(np.deg2rad(pv))
-        sn = np.sin(np.deg2rad(pv))
-        pvmat = np.dot(np.array([[cs,sn],[-sn,cs]]),wcs.parity)
-        rot = np.arctan2(pvmat[0,1],pvmat[1,1])
-        scale = wcs.idcscale/3600.
-
-        det = linalg.det(wcs.parity)
-
-    else:
-
-        det = linalg.det(cd)
-
-        # find pixel scale:
-        if hasattr(wcs, 'idcscale'):
-            scale = (wcs.idcscale) / 3600. # HST pixel scale provided
-        else:
-            scale = np.sqrt(np.abs(det)) # find as sqrt(pixel area)
-
-        # find Y-axis orientation:
-        if hasattr(wcs, 'orientat') and not ignoreHST:
-            rot = np.deg2rad(wcs.orientat) # use HST ORIENTAT
-        else:
-            rot = np.arctan2(wcs.wcs.cd[0,1], wcs.wcs.cd[1,1]) # angle of the Y-axis
-
-    par = -1 if det < 0.0 else 1
-
-    # create a perfectly square, orthogonal WCS
-    sn = np.sin(rot)
-    cs = np.cos(rot)
-    orthogonal_cd = scale * np.array([[par*cs, sn], [-par*sn, cs]])
-
-    lin_wcsobj = pywcs.WCS()
-    lin_wcsobj.wcs.cd = orthogonal_cd
-    lin_wcsobj.wcs.set()
-    lin_wcsobj.orientat = arctan2(lin_wcsobj.wcs.cd[0,1],lin_wcsobj.wcs.cd[1,1]) * 180./np.pi
-    lin_wcsobj.pscale = sqrt(lin_wcsobj.wcs.cd[0,0]**2 + lin_wcsobj.wcs.cd[1,0]**2)*3600.
-    lin_wcsobj.wcs.crval = np.array([0.,0.])
-    lin_wcsobj.wcs.crpix = np.array([0.,0.])
-    lin_wcsobj.wcs.ctype = ['RA---TAN', 'DEC--TAN']
-    lin_wcsobj.wcs.set()
-
-    return lin_wcsobj
-
-def  undistortWCS(wcsobj):
-    """
-    Creates an undistorted linear WCS by applying the IDCTAB distortion model
-    to a 3-point square. The new ORIENTAT angle is calculated as well as the
-    plate scale in the undistorted frame.
-    """
-    assert isinstance(wcsobj, pywcs.WCS)
-    from . import coeff_converter
-
-    cx, cy = coeff_converter.sip2idc(wcsobj)
-    # cx, cy can be None because either there is no model available
-    # or updatewcs was not run.
-    if cx is None or cy is None:
-        if foundIDCTAB(wcsobj.idctab):
-            m = """IDCTAB is present but distortion model is missing.
-            Run updatewcs() to update the headers or
-            pass 'undistort=False' keyword to output_wcs().\n
-            """
-            raise RuntimeError(m)
-        else:
-            print('Distortion model is not available, using input reference image for output WCS.\n')
-            return wcsobj.copy()
-    crpix1 = wcsobj.wcs.crpix[0]
-    crpix2 = wcsobj.wcs.crpix[1]
-    xy = np.array([(crpix1,crpix2),(crpix1+1.,crpix2),(crpix1,crpix2+1.)],dtype=np.double)
-    offsets = np.array([wcsobj.ltv1, wcsobj.ltv2])
-    px = xy + offsets
-    #order = wcsobj.sip.a_order
-    pscale = wcsobj.idcscale
-    #pixref = np.array([wcsobj.sip.SIPREF1, wcsobj.sip.SIPREF2])
-
-    tan_pix = apply_idc(px, cx, cy, wcsobj.wcs.crpix, pscale, order=1)
-    xc = tan_pix[:,0]
-    yc = tan_pix[:,1]
-    am = xc[1] - xc[0]
-    bm = xc[2] - xc[0]
-    cm = yc[1] - yc[0]
-    dm = yc[2] - yc[0]
-    cd_mat = np.array([[am,bm],[cm,dm]],dtype=np.double)
-
-    # Check the determinant for singularity
-    _det = (am * dm) - (bm * cm)
-    if ( _det == 0.0):
-        print('Singular matrix in updateWCS, aborting ...')
-        return
-
-    lin_wcsobj = pywcs.WCS()
-    cd_inv = np.linalg.inv(cd_mat)
-    cd = np.dot(wcsobj.wcs.cd, cd_inv).astype(np.float64)
-    lin_wcsobj.wcs.cd = cd
-    lin_wcsobj.wcs.set()
-    lin_wcsobj.orientat = arctan2(lin_wcsobj.wcs.cd[0,1],lin_wcsobj.wcs.cd[1,1]) * 180./np.pi
-    lin_wcsobj.pscale = sqrt(lin_wcsobj.wcs.cd[0,0]**2 + lin_wcsobj.wcs.cd[1,0]**2)*3600.
-    lin_wcsobj.wcs.crval = np.array([0.,0.])
-    lin_wcsobj.wcs.crpix = np.array([0.,0.])
-    lin_wcsobj.wcs.ctype = ['RA---TAN', 'DEC--TAN']
-    lin_wcsobj.wcs.set()
-    return lin_wcsobj
-
-def apply_idc(pixpos, cx, cy, pixref, pscale= None, order=None):
-    """
-    Apply the IDCTAB polynomial distortion model to pixel positions.
-    pixpos must be already corrected for ltv1/2.
-
-    Parameters
-    ----------
-    pixpos: a 2D numpy array of (x,y) pixel positions to be distortion corrected
-    cx, cy: IDC model distortion coefficients
-    pixref: reference opixel position
-
-    """
-    if cx is None:
-        return pixpos
-
-    if order is None:
-        print('Unknown order of distortion model \n')
-        return pixpos
-    if pscale is None:
-        print('Unknown model plate scale\n')
-        return pixpos
-
-    # Apply in the same way that 'drizzle' would...
-    _cx = cx/pscale
-    _cy = cy/ pscale
-    _p = pixpos
-
-    # Do NOT include any zero-point terms in CX,CY here
-    # as they should not be scaled by plate-scale like rest
-    # of coeffs...  This makes the computations consistent
-    # with 'drizzle'.  WJH 17-Feb-2004
-    _cx[0,0] = 0.
-    _cy[0,0] = 0.
-
-    dxy = _p - pixref
-    # Apply coefficients from distortion model here...
-
-    c = _p * 0.
-    for i in range(order+1):
-        for j in range(i+1):
-            c[:,0] = c[:,0] + _cx[i][j] * pow(dxy[:,0],j) * pow(dxy[:,1],(i-j))
-            c[:,1] = c[:,1] + _cy[i][j] * pow(dxy[:,0],j) * pow(dxy[:,1],(i-j))
-
-    return  c
-
-def foundIDCTAB(idctab):
-    idctab_found = True
-    try:
-        idctab = fileutil.osfn(idctab)
-        if idctab == 'N/A' or idctab == "":
-            idctab_found = False
-        if os.path.exists(idctab):
-            idctab_found = True
-        else:
-            idctab_found = False
-    except KeyError:
-        idctab_found = False
-    return idctab_found
diff --git a/lib/stwcs/gui/__init__.py b/lib/stwcs/gui/__init__.py
deleted file mode 100644
index cd21bf6..0000000
--- a/lib/stwcs/gui/__init__.py
+++ /dev/null
@@ -1,19 +0,0 @@
-""" STWCS.GUI
-
-This package defines the TEAL interfaces for public, file-based operations
-provided by the STWCS package.
-
-"""
-from __future__ import absolute_import # confidence high
-__docformat__ = 'restructuredtext'
-
-# import modules which define the TEAL interfaces 
-from . import write_headerlet
-from . import extract_headerlet
-from . import attach_headerlet
-from . import delete_headerlet
-from . import headerlet_summary
-from . import archive_headerlet
-from . import restore_headerlet
-from . import apply_headerlet
-from . import updatewcs
diff --git a/lib/stwcs/gui/apply_headerlet.help b/lib/stwcs/gui/apply_headerlet.help
deleted file mode 100644
index f701b52..0000000
--- a/lib/stwcs/gui/apply_headerlet.help
+++ /dev/null
@@ -1,38 +0,0 @@
-This task applies a headerlet to a science observation to update either the
-PRIMARY WCS or to add it as an alternate WCS.
-
-filename = ""
-hdrlet = ""
-attach = True
-primary = True
-archive = True
-force = False
-wcskey = ""
-wcsname = ""
-verbose = False
-
-Parameters
-----------
-filename: string, @-file or wild-card name
-         File name(s) of science observation whose WCS solution will be updated
-hdrlet: string, @-file or wild-card name
-         Headerlet file(s), must match input filenames 1-to-1
-attach: boolean
-        True (default): append headerlet to FITS file as a new extension.
-primary: boolean
-        Specify whether or not to replace PRIMARY WCS with WCS from headerlet.
-archive: boolean
-        True (default): before updating, create a headerlet with the
-        WCS old solution.
-force: boolean
-        If True, this will cause the headerlet to replace the current PRIMARY
-        WCS even if it has a different distortion model. [Default: False]
-wcskey: string
-      Key value (A-Z, except O) for this alternate WCS
-      If None, the next available key will be used
-wcsname: string
-      Name to be assigned to this alternate WCS
-      WCSNAME is a required keyword in a Headerlet but this allows the
-      user to change it as desired.
-logging: boolean
-        enable file logging
diff --git a/lib/stwcs/gui/apply_headerlet.py b/lib/stwcs/gui/apply_headerlet.py
deleted file mode 100644
index d517e9f..0000000
--- a/lib/stwcs/gui/apply_headerlet.py
+++ /dev/null
@@ -1,54 +0,0 @@
-import os
-from stsci.tools import teal, parseinput
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    # start by interpreting filename and hdrlet inputs
-    filename = parseinput.parseinput(configObj['filename'])[0]
-    hdrlet = parseinput.parseinput(configObj['hdrlet'])[0]
-
-    if configObj['primary']:
-        # Call function with properly interpreted input parameters
-        # Syntax: apply_headerlet_as_primary(filename, hdrlet, attach=True,
-        #            archive=True, force=False, verbose=False)
-        headerlet.apply_headerlet_as_primary(filename,
-                        hdrlet,attach=configObj['attach'],
-                        archive=configObj['archive'],force=configObj['force'],
-                        logging=configObj['logging'])
-    else:
-        wcsname = configObj['wcsname']
-        if wcsname in ['',' ','INDEF']: wcsname = None
-        wcskey = configObj['wcskey']
-        if wcskey == '': wcskey = None
-        # Call function with properly interpreted input parameters
-        #         apply_headerlet_as_alternate(filename, hdrlet, attach=True,
-        #                        wcskey=None, wcsname=None, verbose=False)
-        headerlet.apply_headerlet_as_alternate(filename,
-                        hdrlet, attach=configObj['attach'],
-                        wcsname=wcsname, wcskey=wcskey,
-                        logging=configObj['logging'])
diff --git a/lib/stwcs/gui/archive_headerlet.py b/lib/stwcs/gui/archive_headerlet.py
deleted file mode 100644
index 7ad3d4d..0000000
--- a/lib/stwcs/gui/archive_headerlet.py
+++ /dev/null
@@ -1,69 +0,0 @@
-from __future__ import print_function
-import os
-
-from astropy.io import fits
-from stsci.tools import teal
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += headerlet.archive_as_headerlet.__doc__
-
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    if configObj['hdrname'] in ['',' ','INDEF']:
-        print('='*60)
-        print('ERROR:')
-        print('    No valid "hdrname" parameter value provided!')
-        print('    Please restart this task and provide a value for this parameter.')
-        print('='*60)
-        return
-
-    str_kw = ['wcsname','destim','sipname','npolfile','d2imfile',
-            'descrip','history','author']
-
-    # create dictionary of remaining parameters, deleting extraneous ones
-    # such as those above
-    cdict = configObj.dict()
-    # remove any rules defined for the TEAL interface
-    if "_RULES_" in cdict: del cdict['_RULES_']
-    del cdict['_task_name_']
-    del cdict['filename']
-    del cdict['hdrname']
-
-    # Convert blank string input as None
-    for kw in str_kw:
-        if cdict[kw] == '': cdict[kw] = None
-    if cdict['wcskey'].lower() == 'primary': cdict['wcskey'] = ' '
-
-    # Call function with properly interpreted input parameters
-    # Syntax: archive_as_headerlet(filename, sciext='SCI', wcsname=None, wcskey=None,
-    #                    hdrname=None, destim=None,
-    #                    sipname=None, npolfile=None, d2imfile=None,
-    #                    author=None, descrip=None, history=None,
-    #                    hdrlet=None, clobber=False)
-    headerlet.archive_as_headerlet(configObj['filename'], configObj['hdrname'],
-                                **cdict)
diff --git a/lib/stwcs/gui/attach_headerlet.py b/lib/stwcs/gui/attach_headerlet.py
deleted file mode 100644
index 873c549..0000000
--- a/lib/stwcs/gui/attach_headerlet.py
+++ /dev/null
@@ -1,36 +0,0 @@
-import os
-
-from stsci.tools import teal
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += eval('.'.join([__package__,__taskname__,'__doc__']))
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    headerlet.attach_headerlet(configObj['filename'],configObj['hdrlet'],
-                               configObj['logging'])
-
diff --git a/lib/stwcs/gui/delete_headerlet.py b/lib/stwcs/gui/delete_headerlet.py
deleted file mode 100644
index b3df5a7..0000000
--- a/lib/stwcs/gui/delete_headerlet.py
+++ /dev/null
@@ -1,52 +0,0 @@
-from __future__ import print_function
-import os
-
-from stsci.tools import teal
-from stsci.tools import parseinput
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += eval('.'.join([__package__,__taskname__,'__doc__']))
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    if configObj['hdrname'] == '' and configObj['hdrext'] is None and \
-        configObj['distname'] == '':
-        print('='*60)
-        print('ERROR:')
-        print('    No valid "hdrname", "hdrext" or "distname" parameter value provided!')
-        print('    Please restart this task and provide a value for one of these parameters.')
-        print('='*60)
-        return
-    filename = parseinput.parseinput(configObj['filename'])[0]
-    # Call function with properly interpreted input parameters
-    # Syntax: delete_headerlet(filename, hdrname=None, hdrext=None, distname=None)
-    headerlet.delete_headerlet(filename,
-                                hdrname = configObj['hdrname'],
-                                hdrext = configObj['hdrext'],
-                                distname = configObj['distname'],
-                                logging = configObj['logging'])
-
diff --git a/lib/stwcs/gui/extract_headerlet.py b/lib/stwcs/gui/extract_headerlet.py
deleted file mode 100644
index 02ecd7a..0000000
--- a/lib/stwcs/gui/extract_headerlet.py
+++ /dev/null
@@ -1,58 +0,0 @@
-from __future__ import print_function
-import os
-
-from stsci.tools import teal
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += eval('.'.join([__package__,__taskname__,'__doc__']))
-
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    if configObj['output'] in ['',' ',None]:
-        print('='*60)
-        print('ERROR:')
-        print('    No valid "output" parameter value provided!')
-        print('    Please restart this task and provide a value for this parameter.')
-        print('='*60)
-        return
-
-    # create dictionary of remaining parameters, deleting extraneous ones
-    # such as those above
-    cdict = configObj.dict()
-    # remove any rules defined for the TEAL interface
-    if "_RULES_" in cdict: del cdict['_RULES_']
-    del cdict['_task_name_']
-    del cdict['filename']
-    del cdict['output']
-
-    # Call function with properly interpreted input parameters
-    # Syntax: extract_headerlet(filename, output, extnum=None, hdrname=None,
-    #                clobber=False, verbose=100)
-    headerlet.extract_headerlet(configObj['filename'], configObj['output'],
-                                **cdict)
-
diff --git a/lib/stwcs/gui/headerlet_summary.py b/lib/stwcs/gui/headerlet_summary.py
deleted file mode 100644
index 82a3e0c..0000000
--- a/lib/stwcs/gui/headerlet_summary.py
+++ /dev/null
@@ -1,47 +0,0 @@
-import os
-from stsci.tools import teal
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += eval('.'.join([__package__,__taskname__,'__doc__']))
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    # create dictionary of remaining parameters, deleting extraneous ones
-    # such as those above
-    cdict = configObj.dict()
-    # remove any rules defined for the TEAL interface
-    if "_RULES_" in cdict: del cdict['_RULES_']
-    del cdict['_task_name_']
-    del cdict['filename']
-    if headerlet.is_par_blank(cdict['columns']):
-        cdict['columns'] = None
-    # Call function with properly interpreted input parameters
-
-    # Syntax: headerlet_summary(filename,columns=None,pad=2,maxwidth=None,
-    #                    output=None,clobber=True,quiet=False)
-    headerlet.headerlet_summary(configObj['filename'],**cdict)
-
diff --git a/lib/stwcs/gui/pars/apply_headerlet.cfg b/lib/stwcs/gui/pars/apply_headerlet.cfg
deleted file mode 100644
index 06d6daf..0000000
--- a/lib/stwcs/gui/pars/apply_headerlet.cfg
+++ /dev/null
@@ -1,10 +0,0 @@
-_task_name_ = apply_headerlet
-filename = ""
-hdrlet = ""
-attach = True
-primary = True
-archive = True
-force = False
-wcskey = ""
-wcsname = ""
-logging = False
diff --git a/lib/stwcs/gui/pars/apply_headerlet.cfgspc b/lib/stwcs/gui/pars/apply_headerlet.cfgspc
deleted file mode 100644
index 648e562..0000000
--- a/lib/stwcs/gui/pars/apply_headerlet.cfgspc
+++ /dev/null
@@ -1,12 +0,0 @@
-_task_name_ = string_kw(default="apply_headerlet")
-filename = string_kw(default="", comment="Input file name")
-hdrlet = string_kw(default="", comment="Headerlet FITS filename")
-attach = boolean_kw(default=True, comment= "Append headerlet to FITS file as new extension?")
-primary = boolean_kw(default=True, triggers="_rule1_", comment="Replace PRIMARY WCS with headerlet WCS?")
-archive = boolean_kw(default=True, active_if="_rule1_", comment="Save PRIMARY WCS as new headerlet extension?")
-force = boolean_kw(default=False, active_if="_rule1_", comment="If distortions do not match, force update anyway?")
-wcskey = option_kw("A","B","C","D","E","F","G","H","I","J","K","L","M","N","P","Q","R","S","T","U","V","W","X","Y","Z","", default="", inactive_if="_rule1_", comment="Apply headerlet as alternate WCS with this letter")
-wcsname = string_kw(default="", inactive_if="_rule1_", comment="Apply headerlet as alternate WCS with this name")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
-[ _RULES_ ]
-_rule1_ = string_kw(default=True, code='tyfn={"yes":True, "no":False}; OUT = tyfn[VAL]')
diff --git a/lib/stwcs/gui/pars/archive_headerlet.cfg b/lib/stwcs/gui/pars/archive_headerlet.cfg
deleted file mode 100644
index 97cd7ef..0000000
--- a/lib/stwcs/gui/pars/archive_headerlet.cfg
+++ /dev/null
@@ -1,14 +0,0 @@
-_task_name_ = archive_headerlet
-filename = ""
-hdrname = ""
-sciext = "SCI"
-wcsname = ""
-wcskey = "PRIMARY"
-destim = ""
-sipname = ""
-npolfile = ""
-d2imfile = ""
-author = ""
-descrip = ""
-history = ""
-logging = False
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/archive_headerlet.cfgspc b/lib/stwcs/gui/pars/archive_headerlet.cfgspc
deleted file mode 100644
index 03e67f0..0000000
--- a/lib/stwcs/gui/pars/archive_headerlet.cfgspc
+++ /dev/null
@@ -1,14 +0,0 @@
-_task_name_ = string_kw(default="archive_headerlet")
-filename = string_kw(default="", comment="Input file name")
-hdrname = string_kw(default="", comment="Unique name(HDRNAME) for headerlet")
-sciext = string_kw(default="SCI", comment="EXTNAME of extension with WCS")
-wcsname = string_kw(default="", comment="Name of WCS to be archived")
-wcskey = option_kw("A","B","C","D","E","F","G","H","I","J","K","L","M","N","P","Q","R","S","T","U","V","W","X","Y","Z","PRIMARY", default="PRIMARY", comment="Archive the WCS with this letter")
-destim = string_kw(default="", comment="Rootname of image to which this headerlet applies ")
-sipname = string_kw(default="", comment="Name for source of polynomial distortion keywords")
-npolfile = string_kw(default="", comment="Name for source of non-polynomial residuals")
-d2imfile = string_kw(default="", comment="Name for source of detector correction table")
-author = string_kw(default="", comment="Author name for creator of headerlet")
-descrip = string_kw(default="", comment="Short description of headerlet solution")
-history = string_kw(default="", comment="Name of ASCII file containing history for headerlet")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/attach_headerlet.cfg b/lib/stwcs/gui/pars/attach_headerlet.cfg
deleted file mode 100644
index d131a70..0000000
--- a/lib/stwcs/gui/pars/attach_headerlet.cfg
+++ /dev/null
@@ -1,4 +0,0 @@
-_task_name_ = attach_headerlet
-filename = ""
-hdrlet = ""
-logging = False
diff --git a/lib/stwcs/gui/pars/attach_headerlet.cfgspc b/lib/stwcs/gui/pars/attach_headerlet.cfgspc
deleted file mode 100644
index bc91bca..0000000
--- a/lib/stwcs/gui/pars/attach_headerlet.cfgspc
+++ /dev/null
@@ -1,4 +0,0 @@
-_task_name_ = string_kw(default="attach_headerlet")
-filename = string_kw(default="", comment="FITS image file name")
-hdrlet = string_kw(default="", comment="Headerlet FITS filename")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/delete_headerlet.cfg b/lib/stwcs/gui/pars/delete_headerlet.cfg
deleted file mode 100644
index d156937..0000000
--- a/lib/stwcs/gui/pars/delete_headerlet.cfg
+++ /dev/null
@@ -1,6 +0,0 @@
-_task_name_ = delete_headerlet
-filename = ""
-hdrname = ""
-hdrext = None
-distname = ""
-logging = False
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/delete_headerlet.cfgspc b/lib/stwcs/gui/pars/delete_headerlet.cfgspc
deleted file mode 100644
index 43790b1..0000000
--- a/lib/stwcs/gui/pars/delete_headerlet.cfgspc
+++ /dev/null
@@ -1,6 +0,0 @@
-_task_name_ = string_kw(default="delete_headerlet")
-filename = string_kw(default="", comment="FITS image file name(s), list or wild-card")
-hdrname = string_kw(default="", comment="Delete headerlet with this HDRNAME")
-hdrext = integer_or_none_kw(default=None, comment="Delete headerlet from this extension")
-distname = string_kw(default="", comment="Delete *ALL* with this DISTNAME")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
diff --git a/lib/stwcs/gui/pars/extract_headerlet.cfg b/lib/stwcs/gui/pars/extract_headerlet.cfg
deleted file mode 100644
index 3dd0a7a..0000000
--- a/lib/stwcs/gui/pars/extract_headerlet.cfg
+++ /dev/null
@@ -1,7 +0,0 @@
-_task_name_ = extract_headerlet
-filename = ""
-output = ""
-extnum = None
-hdrname = ""
-clobber = True
-logging = False
diff --git a/lib/stwcs/gui/pars/extract_headerlet.cfgspc b/lib/stwcs/gui/pars/extract_headerlet.cfgspc
deleted file mode 100644
index b50d4bf..0000000
--- a/lib/stwcs/gui/pars/extract_headerlet.cfgspc
+++ /dev/null
@@ -1,7 +0,0 @@
-_task_name_ = string_kw(default="extract_headerlet")
-filename = string_kw(default="", comment="Input file name")
-output = string_kw(default="", comment="Output headerlet FITS filename")
-extnum = integer_or_none_kw(default=None, comment="FITS extension number of headerlet")
-hdrname = string_kw(default="", comment="Unique name(HDRNAME) for headerlet")
-clobber = boolean_kw(default=True, comment= "Overwrite existing headerlet FITS file?")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
diff --git a/lib/stwcs/gui/pars/headerlet_summary.cfg b/lib/stwcs/gui/pars/headerlet_summary.cfg
deleted file mode 100644
index 7203552..0000000
--- a/lib/stwcs/gui/pars/headerlet_summary.cfg
+++ /dev/null
@@ -1,8 +0,0 @@
-_task_name_ = headerlet_summary
-filename = ""
-columns = None
-pad = 2
-maxwidth = None
-output = ""
-clobber = True
-quiet = False
diff --git a/lib/stwcs/gui/pars/headerlet_summary.cfgspc b/lib/stwcs/gui/pars/headerlet_summary.cfgspc
deleted file mode 100644
index ce65930..0000000
--- a/lib/stwcs/gui/pars/headerlet_summary.cfgspc
+++ /dev/null
@@ -1,8 +0,0 @@
-_task_name_ = string_kw(default="headerlet_summary")
-filename = string_kw(default="", comment="FITS image file name")
-columns = string_kw(default="", comment="Headerlet keyword(s) to be reported")
-pad = integer_kw(default=2, comment="Number of spaces between output columns")
-maxwidth = integer_or_none_kw(default=None, comment="Max width for each column")
-output = string_kw(default="", comment="Name of output file for summary")
-clobber = boolean_kw(default=True, comment="Overwrite previously written summary?")
-quiet = boolean_kw(default=False, comment="Suppress output of summary to STDOUT?")
diff --git a/lib/stwcs/gui/pars/restore_headerlet.cfg b/lib/stwcs/gui/pars/restore_headerlet.cfg
deleted file mode 100644
index b0ec427..0000000
--- a/lib/stwcs/gui/pars/restore_headerlet.cfg
+++ /dev/null
@@ -1,10 +0,0 @@
-_task_name_ = restore_headerlet
-filename = ""
-archive = True
-force = False
-distname = ""
-primary = None
-sciext = "SCI"
-hdrname = ""
-hdrext = None
-logging = False
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/restore_headerlet.cfgspc b/lib/stwcs/gui/pars/restore_headerlet.cfgspc
deleted file mode 100644
index df47e3f..0000000
--- a/lib/stwcs/gui/pars/restore_headerlet.cfgspc
+++ /dev/null
@@ -1,12 +0,0 @@
-_task_name_ = string_kw(default="restore_headerlet")
-filename = string_kw(default="", comment="Input file name")
-archive = boolean_kw(default=True, comment= "Create headerlets from WCSs being replaced?")
-force = boolean_kw(default=False, comment="If distortions do not match, force update anyway?")
-distname = string_kw(default="", triggers="_rule1_", comment="Restore ALL headerlet extensions with this DISTNAME")
-primary = integer_or_none_kw(default=None, inactive_if="_rule1_", comment="Headerlet extension to restore as new primary WCS")
-sciext = string_kw(default="SCI", inactive_if="_rule1_", comment="EXTNAME of extension with WCS")
-hdrname = string_kw(default="", active_if="_rule1_", comment="HDRNAME of headerlet extension to be restored")
-hdrext = integer_or_none_kw(default=None, active_if="_rule1_", comment="Extension number for headerlet to be restored")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
-[ _RULES_ ]
-_rule1_ = string_kw(default=True, code='from stwcs import wcsutil;from stwcs.wcsutil import headerlet;OUT = headerlet.is_par_blank(VAL)')
diff --git a/lib/stwcs/gui/pars/updatewcs.cfg b/lib/stwcs/gui/pars/updatewcs.cfg
deleted file mode 100644
index 35360f2..0000000
--- a/lib/stwcs/gui/pars/updatewcs.cfg
+++ /dev/null
@@ -1,8 +0,0 @@
-_task_name_ = updatewcs
-input = "*flt.fits"
-extname = "SCI"
-vacorr = True
-tddcorr = True
-npolcorr = True
-d2imcorr = True
-checkfiles = True
diff --git a/lib/stwcs/gui/pars/updatewcs.cfgspc b/lib/stwcs/gui/pars/updatewcs.cfgspc
deleted file mode 100644
index a3a3fb5..0000000
--- a/lib/stwcs/gui/pars/updatewcs.cfgspc
+++ /dev/null
@@ -1,8 +0,0 @@
-_task_name_ = string_kw(default="updatewcs")
-input = string_kw(default="", comment="Input files (name, suffix, or @list)")
-extname = string_kw(default="SCI", comment="EXTNAME of extensions to be archived")
-vacorr = boolean_kw(default=True, comment= "Apply velocity aberration correction?")
-tddcorr = boolean_kw(default=True, comment= "Apply time dependent distortion correction?")
-npolcorr = boolean_kw(default=True, comment= "Apply lookup table distortion?")
-d2imcorr = boolean_kw(default=True, comment= "Apply detector to image correction?")
-checkfiles = boolean_kw(default=True, comment= "Check format of input files?")
diff --git a/lib/stwcs/gui/pars/write_headerlet.cfg b/lib/stwcs/gui/pars/write_headerlet.cfg
deleted file mode 100644
index 9eb4592..0000000
--- a/lib/stwcs/gui/pars/write_headerlet.cfg
+++ /dev/null
@@ -1,18 +0,0 @@
-_task_name_ = write_headerlet
-filename = ""
-output = ""
-clobber = True
-hdrname = ""
-wcskey = "PRIMARY"
-wcsname = ""
-author = ""
-descrip = ""
-catalog = ""
-history = ""
-sciext = "SCI"
-destim = ""
-sipname = ""
-npolfile = ""
-d2imfile = ""
-attach = True
-logging = False
\ No newline at end of file
diff --git a/lib/stwcs/gui/pars/write_headerlet.cfgspc b/lib/stwcs/gui/pars/write_headerlet.cfgspc
deleted file mode 100644
index ba28b05..0000000
--- a/lib/stwcs/gui/pars/write_headerlet.cfgspc
+++ /dev/null
@@ -1,18 +0,0 @@
-_task_name_ = string_kw(default="write_headerlet")
-filename = string_kw(default="", comment="Input file name")
-output = string_kw(default="", comment="Filename for headerlet FITS file")
-clobber = boolean_kw(default=True, comment= "Overwrite existing headerlet FITS file?")
-hdrname = string_kw(default="", comment="Unique name(HDRNAME) for headerlet[REQUIRED]")
-wcskey = option_kw("A","B","C","D","E","F","G","H","I","J","K","L","M","N","P","Q","R","S","T","U","V","W","X","Y","Z","PRIMARY", default="PRIMARY", comment="Create headerlet from WCS with this letter")
-wcsname = string_kw(default="", comment="Create headerlet from WCS with this name")
-author = string_kw(default="", comment="Author name for creator of headerlet")
-descrip = string_kw(default="", comment="Short description of headerlet solution")
-catalog = string_kw(default="", comment="Reference frame for headerlet solution")
-history = string_kw(default="", comment="Name of ASCII file containing history for headerlet")
-sciext = string_kw(default="SCI", comment="EXTNAME of extension with WCS")
-destim = string_kw(default="", comment="Rootname of image to which this headerlet applies ")
-sipname = string_kw(default="", comment="Name for source of polynomial distortion keywords")
-npolfile = string_kw(default="", comment="Name for source of non-polynomial residuals")
-d2imfile = string_kw(default="", comment="Name for source of detector correction table")
-attach = boolean_kw(default=True, comment="Create headerlet FITS extension?")
-logging = boolean_kw(default=False, comment= "Enable logging to a file")
\ No newline at end of file
diff --git a/lib/stwcs/gui/restore_headerlet.help b/lib/stwcs/gui/restore_headerlet.help
deleted file mode 100644
index fe07a15..0000000
--- a/lib/stwcs/gui/restore_headerlet.help
+++ /dev/null
@@ -1,43 +0,0 @@
-Restore headerlet extension(s) as either a primary WCS or as alternate WCSs
-
-This task can restore a WCS solution stored in a headerlet extension or 
-restore all WCS solutions from all headerlet extensions with the same 
-distortion model. 
-
-Parameters
-----------
-filename: string or HDUList
-    Either a filename or PyFITS HDUList object for the input science file
-    An input filename (str) will be expanded as necessary to interpret 
-    any environmental variables included in the filename.
-
-archive: boolean (default True)
-    flag indicating if HeaderletHDUs should be created from the
-    primary and alternate WCSs in fname before restoring all matching
-    headerlet extensions
-
-force: boolean (default:False)
-    When the distortion models of the headerlet and the primary do
-    not match, and archive is False, this flag forces an update of
-    the primary.
-
-distname: string 
-    distortion model as represented by a DISTNAME keyword         
-
-primary: int or string or None
-    HeaderletHDU to be restored as primary
-    if int - a fits extension
-    if string - HDRNAME
-    if None - use first HeaderletHDU
-
-sciext: string (default: SCI)
-    EXTNAME value of FITS extensions with WCS keywords
-
-hdrname: string
-    HDRNAME keyword of HeaderletHDU 
-
-hdrext: int or tuple
-    Headerlet extension number of tuple ('HDRLET',2) 
-
-logging: boolean
-        enable file logging
\ No newline at end of file
diff --git a/lib/stwcs/gui/restore_headerlet.py b/lib/stwcs/gui/restore_headerlet.py
deleted file mode 100644
index 7570d76..0000000
--- a/lib/stwcs/gui/restore_headerlet.py
+++ /dev/null
@@ -1,48 +0,0 @@
-import os
-
-from stsci.tools import teal
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    if configObj['distname'] not in ['',' ','INDEF']:
-        # Call function with properly interpreted input parameters
-        # Syntax: restore_all_with_distname(filename, distname, primary,
-        #           archive=True, sciext='SCI', verbose=False)
-        headerlet.restore_all_with_distname(configObj['filename'],
-                        configObj['distname'],configObj['primary'],
-                        archive=configObj['archive'],sciext=configObj['sciext'],
-                        logging=configObj['logging'])
-    else:
-        # Call function with properly interpreted input parameters
-        #         restore_from_headerlet(filename, hdrname=None, hdrext=None,
-        #           archive=True, force=False)
-        headerlet.restore_from_headerlet(configObj['filename'],
-                        hdrname=configObj['hdrname'],hdrext=configObj['hdrext'],
-                        archive=configObj['archive'], force=configObj['force'],
-                        logging=configObj['logging'])
-
diff --git a/lib/stwcs/gui/updatewcs.py b/lib/stwcs/gui/updatewcs.py
deleted file mode 100644
index 3dacb67..0000000
--- a/lib/stwcs/gui/updatewcs.py
+++ /dev/null
@@ -1,90 +0,0 @@
-from __future__ import print_function
-import os
-
-from astropy.io import fits
-from stsci.tools import parseinput
-from stsci.tools import fileutil
-from stsci.tools import teal
-import stwcs
-from stwcs import updatewcs
-from stwcs.wcsutil import convertwcs
-
-allowed_corr_dict = {'vacorr':'VACorr','tddcorr':'TDDCorr','npolcorr':'NPOLCorr','d2imcorr':'DET2IMCorr'}
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = updatewcs.__name__
-__version__ = stwcs.__version__
-
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += eval('.'.join([__package__,__taskname__,'__doc__']))
-
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-
-    # Interpret primary parameters from configObj instance
-    extname = configObj['extname']
-    input = configObj['input']
-
-    # create dictionary of remaining parameters, deleting extraneous ones
-    # such as those above
-    cdict = configObj.dict()
-    # remove any rules defined for the TEAL interface
-    if "_RULES_" in cdict: del cdict['_RULES_']
-    del cdict['_task_name_']
-    del cdict['input']
-    del cdict['extname']
-
-    # parse input
-    input,altfiles = parseinput.parseinput(configObj['input'])
-
-    # Insure that all input files have a correctly archived
-    #    set of OPUS WCS keywords
-    # Legacy files from OTFR, like all WFPC2 data from OTFR, will only
-    #   have the OPUS WCS keywords archived using a prefix of 'O'
-    # These keywords need to be converted to the Paper I alternate WCS
-    #   standard using a wcskey (suffix) of 'O'
-    # If an alternate WCS with wcskey='O' already exists, this will copy
-    #   the values from the old prefix-'O' WCS keywords to insure the correct
-    #   OPUS keyword values get archived for use with updatewcs.
-    #
-    for file in input:
-        # Check to insure that there is a valid reference file to be used
-        idctab = fits.getval(file, 'idctab')
-        if not os.path.exists(fileutil.osfn(idctab)):
-            print('No valid distortion reference file ',idctab,' found in ',file,'!')
-            raise ValueError
-
-    # Re-define 'cdict' to only have switches for steps supported by that instrument
-    # the set of supported steps are defined by the dictionary
-    #    updatewcs.apply_corrections.allowed_corrections
-    #
-    for file in input:
-        # get instrument name from input file
-        instr = fits.getval(file,'INSTRUME')
-        # make copy of input parameters dict for this file
-        fdict = cdict.copy()
-        # Remove any parameter that is not part of this instrument's allowed corrections
-        for step in allowed_corr_dict:
-            if allowed_corr_dict[step] not in updatewcs.apply_corrections.allowed_corrections[instr]:
-                fdict[step]
-        # Call 'updatewcs' on correctly archived file
-        updatewcs.updatewcs(file,**fdict)
-
diff --git a/lib/stwcs/gui/write_headerlet.py b/lib/stwcs/gui/write_headerlet.py
deleted file mode 100644
index e18bed8..0000000
--- a/lib/stwcs/gui/write_headerlet.py
+++ /dev/null
@@ -1,80 +0,0 @@
-from __future__ import print_function
-import os
-
-from stsci.tools import teal
-from stsci.tools import parseinput
-
-import stwcs
-from stwcs.wcsutil import headerlet
-
-__taskname__ = __name__.split('.')[-1] # needed for help string
-__package__ = headerlet.__name__
-__version__ = stwcs.__version__
-#
-#### Interfaces used by TEAL
-#
-def getHelpAsString(docstring=False):
-    """
-    return useful help from a file in the script directory called __taskname__.help
-    """
-    install_dir = os.path.dirname(__file__)
-    htmlfile = os.path.join(install_dir,'htmlhelp',__taskname__+'.html')
-    helpfile = os.path.join(install_dir,__taskname__+'.help')
-    if docstring or (not docstring and not os.path.exists(htmlfile)):
-        helpString = __taskname__+' Version '+__version__+'\n\n'
-        if os.path.exists(helpfile):
-            helpString += teal.getHelpFileAsString(__taskname__,__file__)
-        else:
-            helpString += headerlet.write_headerlet.__doc__
-
-    else:
-        helpString = 'file://'+htmlfile
-
-    return helpString
-
-def run(configObj=None):
-    flist,oname = parseinput.parseinput(configObj['filename'])
-    if len(flist) == 0:
-        print('='*60)
-        print('ERROR:')
-        print('    No valid "filename" parameter value provided!')
-        print('    Please check the working directory and restart this task.')
-        print('='*60)
-        return
-
-    if configObj['hdrname'] in ['',' ','INDEF']:
-        print('='*60)
-        print('ERROR:')
-        print('    No valid "hdrname" parameter value provided!')
-        print('    Please restart this task and provide a value for this parameter.')
-        print('='*60)
-        return
-
-    if configObj['output'] in ['',' ','INDEF']:
-        configObj['output'] = None
-
-    str_kw = ['wcsname','destim','sipname','npolfile','d2imfile',
-            'descrip','history','author','output','catalog']
-
-    # create dictionary of remaining parameters, deleting extraneous ones
-    # such as those above
-    cdict = configObj.dict()
-    # remove any rules defined for the TEAL interface
-    if "_RULES_" in cdict: del cdict['_RULES_']
-    del cdict['_task_name_']
-    del cdict['filename']
-    del cdict['hdrname']
-
-    # Convert blank string input as None
-    for kw in str_kw:
-        if cdict[kw] == '': cdict[kw] = None
-    if cdict['wcskey'].lower() == 'primary': cdict['wcskey'] = ' '
-
-    # Call function with properly interpreted input parameters
-    # Syntax: write_headerlet(filename, hdrname, output, sciext='SCI',
-    #                    wcsname=None, wcskey=None, destim=None,
-    #                    sipname=None, npolfile=None, d2imfile=None,
-    #                    author=None, descrip=None, history=None,
-    #                    attach=True, clobber=False)
-    headerlet.write_headerlet(flist, configObj['hdrname'],
-                              **cdict)
diff --git a/lib/stwcs/updatewcs/__init__.py b/lib/stwcs/updatewcs/__init__.py
deleted file mode 100644
index eb5e850..0000000
--- a/lib/stwcs/updatewcs/__init__.py
+++ /dev/null
@@ -1,376 +0,0 @@
-from __future__ import absolute_import, division, print_function # confidence high
-
-from astropy.io import fits
-from stwcs import wcsutil
-from stwcs.wcsutil import HSTWCS
-import stwcs
-
-from astropy import wcs as pywcs
-import astropy
-
-from . import utils, corrections, makewcs
-from . import npol, det2im
-from stsci.tools import parseinput, fileutil
-from . import apply_corrections
-
-import time
-import logging
-logger = logging.getLogger('stwcs.updatewcs')
-
-import atexit
-atexit.register(logging.shutdown)
-
-#Note: The order of corrections is important
-
-def updatewcs(input, vacorr=True, tddcorr=True, npolcorr=True, d2imcorr=True,
-              checkfiles=True, verbose=False):
-    """
-
-    Updates HST science files with the best available calibration information.
-    This allows users to retrieve from the archive self contained science files
-    which do not require additional reference files.
-
-    Basic WCS keywords are updated in the process and new keywords (following WCS
-    Paper IV and the SIP convention) as well as new extensions are added to the science files.
-
-
-    Example
-    -------
-    >>>from stwcs import updatewcs
-    >>>updatewcs.updatewcs(filename)
-
-    Dependencies
-    ------------
-    `stsci.tools`
-    `astropy.io.fits`
-    `astropy.wcs`
-
-    Parameters
-    ----------
-    input: a python list of file names or a string (wild card characters allowed)
-             input files may be in fits, geis or waiver fits format
-    vacorr: boolean
-              If True, vecocity aberration correction will be applied
-    tddcorr: boolean
-             If True, time dependent distortion correction will be applied
-    npolcorr: boolean
-              If True, a Lookup table distortion will be applied
-    d2imcorr: boolean
-              If True, detector to image correction will be applied
-    checkfiles: boolean
-              If True, the format of the input files will be checked,
-              geis and waiver fits files will be converted to MEF format.
-              Default value is True for standalone mode.
-    """
-    if verbose == False:
-        logger.setLevel(100)
-    else:
-        formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
-        log_filename = 'stwcs.log'
-        fh = logging.FileHandler(log_filename, mode='w')
-        fh.setLevel(logging.DEBUG)
-        fh.setFormatter(formatter)
-        logger.addHandler(fh)
-        logger.setLevel(verbose)
-    args = "vacorr=%s, tddcorr=%s, npolcorr=%s, d2imcorr=%s, checkfiles=%s, \
-    " % (str(vacorr), str(tddcorr), str(npolcorr),
-                                          str(d2imcorr), str(checkfiles))
-    logger.info('\n\tStarting UPDATEWCS: %s', time.asctime())
-
-    files = parseinput.parseinput(input)[0]
-    logger.info("\n\tInput files: %s, " % [i for i in files])
-    logger.info("\n\tInput arguments: %s" %args)
-    if checkfiles:
-        files = checkFiles(files)
-        if not files:
-            print('No valid input, quitting ...\n')
-            return
-
-    for f in files:
-        acorr = apply_corrections.setCorrections(f, vacorr=vacorr, \
-            tddcorr=tddcorr,npolcorr=npolcorr, d2imcorr=d2imcorr)
-        if 'MakeWCS' in acorr and newIDCTAB(f):
-            logger.warning("\n\tNew IDCTAB file detected. All current WCSs will be deleted")
-            cleanWCS(f)
-
-        makecorr(f, acorr)
-
-    return files
-
-def makecorr(fname, allowed_corr):
-    """
-    Purpose
-    =======
-    Applies corrections to the WCS of a single file
-
-    :Parameters:
-    `fname`: string
-             file name
-    `acorr`: list
-             list of corrections to be applied
-    """
-    logger.info("Allowed corrections: {0}".format(allowed_corr))
-    f = fits.open(fname, mode='update')
-    #Determine the reference chip and create the reference HSTWCS object
-    nrefchip, nrefext = getNrefchip(f)
-    wcsutil.restoreWCS(f, nrefext, wcskey='O')
-    rwcs = HSTWCS(fobj=f, ext=nrefext)
-    rwcs.readModel(update=True,header=f[nrefext].header)
-
-    if 'DET2IMCorr' in allowed_corr:
-        kw2update = det2im.DET2IMCorr.updateWCS(f)
-        for kw in kw2update:
-            f[1].header[kw] = kw2update[kw]
-
-    for i in range(len(f))[1:]:
-        extn = f[i]
-
-        if 'extname' in extn.header:
-            extname = extn.header['extname'].lower()
-            if  extname == 'sci':
-                wcsutil.restoreWCS(f, ext=i, wcskey='O')
-                sciextver = extn.header['extver']
-                ref_wcs = rwcs.deepcopy()
-                hdr = extn.header
-                ext_wcs = HSTWCS(fobj=f, ext=i)
-                ### check if it exists first!!!
-                # 'O ' can be safely archived again because it has been restored first.
-                wcsutil.archiveWCS(f, ext=i, wcskey="O", wcsname="OPUS", reusekey=True)
-                ext_wcs.readModel(update=True,header=hdr)
-                for c in allowed_corr:
-                    if c != 'NPOLCorr' and c != 'DET2IMCorr':
-                        corr_klass = corrections.__getattribute__(c)
-                        kw2update = corr_klass.updateWCS(ext_wcs, ref_wcs)
-                        for kw in kw2update:
-                            hdr[kw] = kw2update[kw]
-                # give the primary WCS a WCSNAME value
-                idcname = f[0].header.get('IDCTAB', " ")
-                if idcname.strip() and 'idc.fits' in idcname:
-                    wname = ''.join(['IDC_',
-                                utils.extract_rootname(idcname,suffix='_idc')])
-                else: wname = " "
-                hdr['WCSNAME'] = wname
-
-            elif extname in ['err', 'dq', 'sdq', 'samp', 'time']:
-                cextver = extn.header['extver']
-                if cextver == sciextver:
-                    hdr = f[('SCI',sciextver)].header
-                    w = pywcs.WCS(hdr, f)
-                    copyWCS(w, extn.header)
-
-            else:
-                continue
-
-    if 'NPOLCorr' in allowed_corr:
-        kw2update = npol.NPOLCorr.updateWCS(f)
-        for kw in kw2update:
-            f[1].header[kw] = kw2update[kw]
-    # Finally record the version of the software which updated the WCS
-    if 'HISTORY' in f[0].header:
-        f[0].header.set('UPWCSVER', value=stwcs.__version__,
-                        comment="Version of STWCS used to updated the WCS",
-                        before='HISTORY')
-        f[0].header.set('PYWCSVER', value=astropy.__version__,
-                        comment="Version of PYWCS used to updated the WCS",
-                        before='HISTORY')
-    elif 'ASN_MTYP' in f[0].header:
-        f[0].header.set('UPWCSVER', value=stwcs.__version__,
-                        comment="Version of STWCS used to updated the WCS",
-                        after='ASN_MTYP')
-        f[0].header.set('PYWCSVER', value=astropy.__version__,
-                        comment="Version of PYWCS used to updated the WCS",
-                        after='ASN_MTYP')
-    else:
-        # Find index of last non-blank card, and insert this new keyword after that card
-        for i in range(len(f[0].header) - 1, 0, -1):
-            if f[0].header[i].strip() != '':
-                break
-            f[0].header.set('UPWCSVER', stwcs.__version__,
-                            "Version of STWCS used to updated the WCS",
-                            after=i)
-            f[0].header.set('PYWCSVER', astropy.__version__,
-                            "Version of PYWCS used to updated the WCS",
-                            after=i)
-    # add additional keywords to be used by headerlets
-    distdict = utils.construct_distname(f,rwcs)
-    f[0].header['DISTNAME'] = distdict['DISTNAME']
-    f[0].header['SIPNAME'] = distdict['SIPNAME']
-    # Make sure NEXTEND keyword remains accurate
-    f[0].header['NEXTEND'] = len(f)-1
-    f.close()
-
-def copyWCS(w, ehdr):
-    """
-    This is a convenience function to copy a WCS object
-    to a header as a primary WCS. It is used only to copy the
-    WCS of the 'SCI' extension to the headers of 'ERR', 'DQ', 'SDQ',
-    'TIME' or 'SAMP' extensions.
-    """
-    hwcs = w.to_header()
-
-    if w.wcs.has_cd():
-        wcsutil.pc2cd(hwcs)
-    for k in hwcs.keys():
-        key = k[:7]
-        ehdr[key] = hwcs[k]
-
-def getNrefchip(fobj):
-    """
-
-    Finds which FITS extension holds the reference chip.
-
-    The reference chip has EXTNAME='SCI', can be in any extension and
-    is instrument specific. This functions provides mappings between
-    sci extensions, chips and fits extensions.
-    In the case of a subarray when the reference chip is missing, the
-    first 'SCI' extension is the reference chip.
-
-    Parameters
-    ----------
-    fobj: `astropy.io.fits.HDUList` object
-    """
-    nrefext = 1
-    nrefchip = 1
-    instrument = fobj[0].header['INSTRUME']
-
-    if instrument == 'WFPC2':
-        chipkw = 'DETECTOR'
-        extvers = [("SCI",img.header['EXTVER']) for img in
-                   fobj[1:] if img.header['EXTNAME'].lower()=='sci']
-        detectors = [img.header[chipkw] for img in fobj[1:] if
-                     img.header['EXTNAME'].lower()=='sci']
-        fitsext = [i for i in range(len(fobj))[1:] if
-                   fobj[i].header['EXTNAME'].lower()=='sci']
-        det2ext=dict(list(zip(detectors, extvers)))
-        ext2det=dict(list(zip(extvers, detectors)))
-        ext2fitsext=dict(list(zip(extvers, fitsext)))
-
-        if 3 not in detectors:
-            nrefchip = ext2det.pop(extvers[0])
-            nrefext = ext2fitsext.pop(extvers[0])
-        else:
-            nrefchip = 3
-            extname = det2ext.pop(nrefchip)
-            nrefext = ext2fitsext.pop(extname)
-
-    elif (instrument == 'ACS' and fobj[0].header['DETECTOR'] == 'WFC') or \
-         (instrument == 'WFC3' and fobj[0].header['DETECTOR'] == 'UVIS'):
-        chipkw = 'CCDCHIP'
-        extvers = [("SCI",img.header['EXTVER']) for img in
-                   fobj[1:] if img.header['EXTNAME'].lower()=='sci']
-        detectors = [img.header[chipkw] for img in fobj[1:] if
-                     img.header['EXTNAME'].lower()=='sci']
-        fitsext = [i for i in range(len(fobj))[1:] if
-                   fobj[i].header['EXTNAME'].lower()=='sci']
-        det2ext=dict(list(zip(detectors, extvers)))
-        ext2det=dict(list(zip(extvers, detectors)))
-        ext2fitsext=dict(list(zip(extvers, fitsext)))
-
-        if 2 not in detectors:
-            nrefchip = ext2det.pop(extvers[0])
-            nrefext = ext2fitsext.pop(extvers[0])
-        else:
-            nrefchip = 2
-            extname = det2ext.pop(nrefchip)
-            nrefext = ext2fitsext.pop(extname)
-    else:
-        for i in range(len(fobj)):
-            extname = fobj[i].header.get('EXTNAME', None)
-            if extname != None and extname.lower == 'sci':
-                nrefext = i
-                break
-
-    return nrefchip, nrefext
-
-def checkFiles(input):
-    """
-    Checks that input files are in the correct format.
-    Converts geis and waiver fits files to multiextension fits.
-    """
-    from stsci.tools.check_files import geis2mef, waiver2mef, checkFiles
-    logger.info("\n\tChecking files %s" % input)
-    removed_files = []
-    newfiles = []
-    if not isinstance(input, list):
-        input=[input]
-
-    for file in input:
-        try:
-                imgfits,imgtype = fileutil.isFits(file)
-        except IOError:
-            logger.warning( "\n\tFile %s could not be found, removing it from the input list.\n" %file)
-            removed_files.append(file)
-            continue
-        # Check for existence of waiver FITS input, and quit if found.
-        # Or should we print a warning and continue but not use that file
-        if imgfits:
-            if imgtype == 'waiver':
-                newfilename = waiver2mef(file, convert_dq=True)
-                if newfilename == None:
-                    logger.warning("\n\tRemoving file %s from input list - could not convert waiver to mef" %file)
-                    removed_files.append(file)
-                else:
-                    newfiles.append(newfilename)
-            else:
-                newfiles.append(file)
-
-        # If a GEIS image is provided as input, create a new MEF file with
-        # a name generated using 'buildFITSName()'
-        # Convert the corresponding data quality file if present
-        if not imgfits:
-            newfilename = geis2mef(file, convert_dq=True)
-            if newfilename == None:
-                logger.warning("\n\tRemoving file %s from input list - could not convert geis to mef" %file)
-                removed_files.append(file)
-            else:
-                newfiles.append(newfilename)
-    if removed_files:
-        logger.warning('\n\tThe following files will be removed from the list of files to be processed %s' % removed_files)
-
-    newfiles = checkFiles(newfiles)[0]
-    logger.info("\n\tThese files passed the input check and will be processed: %s" % newfiles)
-    return newfiles
-
-def newIDCTAB(fname):
-    #When this is called we know there's a kw IDCTAB in the header
-    hdul = fits.open(fname)
-    idctab = fileutil.osfn(hdul[0].header['IDCTAB'])
-    try:
-        #check for the presence of IDCTAB in the first extension
-        oldidctab = fileutil.osfn(hdul[1].header['IDCTAB'])
-    except KeyError:
-        return False
-    if idctab == oldidctab:
-        return False
-    else:
-        return True
-
-def cleanWCS(fname):
-    # A new IDCTAB means all previously computed WCS's are invalid
-    # We are deleting all of them except the original OPUS WCS.
-    f = fits.open(fname, mode='update')
-    keys = wcsutil.wcskeys(f[1].header)
-    # Remove the primary WCS from the list
-    try:
-        keys.remove(' ')
-    except ValueError:
-        pass
-    fext = list(range(1, len(f)))
-    for key in keys:
-        try:
-            wcsutil.deleteWCS(fname, ext=fext, wcskey=key)
-        except KeyError:
-            # Some extensions don't have the alternate (or any) WCS keywords
-            continue
-
-def getCorrections(instrument):
-    """
-    Print corrections available for an instrument
-
-    :Parameters:
-    `instrument`: string, one of 'WFPC2', 'NICMOS', 'STIS', 'ACS', 'WFC3'
-    """
-    acorr = apply_corrections.allowed_corrections[instrument]
-
-    print("The following corrections will be performed for instrument %s\n" % instrument)
-    for c in acorr: print(c,': ' ,  apply_corrections.cnames[c])
diff --git a/lib/stwcs/updatewcs/apply_corrections.py b/lib/stwcs/updatewcs/apply_corrections.py
deleted file mode 100644
index 86b623a..0000000
--- a/lib/stwcs/updatewcs/apply_corrections.py
+++ /dev/null
@@ -1,248 +0,0 @@
-from __future__ import division, print_function  # confidence high
-
-import os
-from astropy.io import fits
-import time
-from stsci.tools import fileutil
-import os.path
-from stwcs.wcsutil import altwcs
-from . import utils
-from . import wfpc2_dgeo
-
-import logging
-logger = logging.getLogger("stwcs.updatewcs.apply_corrections")
-
-#Note: The order of corrections is important
-
-
-# A dictionary which lists the allowed corrections for each instrument.
-# These are the default corrections applied also in the pipeline.
-
-allowed_corrections={'WFPC2': ['DET2IMCorr', 'MakeWCS','CompSIP', 'VACorr'],
-                    'ACS': ['DET2IMCorr', 'TDDCorr', 'MakeWCS', 'CompSIP','VACorr', 'NPOLCorr'],
-                    'STIS': ['MakeWCS', 'CompSIP','VACorr'],
-                    'NICMOS': ['MakeWCS', 'CompSIP','VACorr'],
-                    'WFC3': ['DET2IMCorr', 'MakeWCS', 'CompSIP','VACorr', 'NPOLCorr'],
-                    }
-
-cnames = {'DET2IMCorr': 'Detector to Image Correction',
-         'TDDCorr': 'Time Dependent Distortion Correction',
-         'MakeWCS': 'Recalculate basic WCS keywords based on the distortion model',
-         'CompSIP': 'Given IDCTAB distortion model calculate the SIP coefficients',
-         'VACorr':  'Velocity Aberration Correction',
-         'NPOLCorr': 'Lookup Table Distortion'
-         }
-
-def setCorrections(fname, vacorr=True, tddcorr=True, npolcorr=True, d2imcorr=True):
-    """
-    Creates a list of corrections to be applied to a file
-    based on user input paramters and allowed corrections
-    for the instrument.
-    """
-    instrument = fits.getval(fname, 'INSTRUME')
-    # make a copy of this list !
-    acorr = allowed_corrections[instrument][:]
-
-    # For WFPC2 images, the old-style DGEOFILE needs to be
-    # converted on-the-fly into a proper D2IMFILE here...
-    if instrument == 'WFPC2':
-        # check for DGEOFILE, and convert it to D2IMFILE if found
-        d2imfile = wfpc2_dgeo.update_wfpc2_d2geofile(fname)
-    # Check if idctab is present on disk
-    # If kw IDCTAB is present in the header but the file is
-    # not found on disk, do not run TDDCorr, MakeCWS and CompSIP
-    if not foundIDCTAB(fname):
-        if 'TDDCorr' in acorr: acorr.remove('TDDCorr')
-        if 'MakeWCS' in acorr: acorr.remove('MakeWCS')
-        if 'CompSIP' in acorr: acorr.remove('CompSIP')
-
-    if 'VACorr' in acorr and vacorr==False:  acorr.remove('VACorr')
-    if 'TDDCorr' in acorr:
-        tddcorr = applyTDDCorr(fname, tddcorr)
-        if tddcorr == False: acorr.remove('TDDCorr')
-
-    if 'NPOLCorr' in acorr:
-        npolcorr = applyNpolCorr(fname, npolcorr)
-        if npolcorr == False: acorr.remove('NPOLCorr')
-    if 'DET2IMCorr' in acorr:
-        d2imcorr = applyD2ImCorr(fname, d2imcorr)
-        if d2imcorr == False: acorr.remove('DET2IMCorr')
-    logger.info("\n\tCorrections to be applied to %s: %s " % (fname, str(acorr)))
-    return acorr
-
-
-def foundIDCTAB(fname):
-    """
-    This functions looks for an "IDCTAB" keyword in the primary header.
-
-    Returns
-    -------
-    status : bool
-        If False : MakeWCS, CompSIP and TDDCorr should not be applied.
-        If True : there's no restriction on corrections, they all should be applied.
-
-    Raises
-    ------
-    IOError : If IDCTAB file not found on disk.
-    """
-
-    try:
-        idctab = fits.getval(fname, 'IDCTAB').strip()
-        if idctab == 'N/A' or idctab == "":
-            return False
-    except KeyError:
-        return False
-    idctab = fileutil.osfn(idctab)
-    if os.path.exists(idctab):
-        return True
-    else:
-        raise IOError("IDCTAB file {0} not found".format(idctab))
-
-
-def applyTDDCorr(fname, utddcorr):
-    """
-    The default value of tddcorr for all ACS images is True.
-    This correction will be performed if all conditions below are True:
-    - the user did not turn it off on the command line
-    - the detector is WFC
-    - the idc table specified in the primary header is available.
-    """
-
-    phdr = fits.getheader(fname)
-    instrument = phdr['INSTRUME']
-    try:
-        detector = phdr['DETECTOR']
-    except KeyError:
-        detector = None
-    try:
-        tddswitch = phdr['TDDCORR']
-    except KeyError:
-        tddswitch = 'PERFORM'
-
-    if instrument == 'ACS' and detector == 'WFC' and utddcorr == True and tddswitch == 'PERFORM':
-        tddcorr = True
-        try:
-            idctab = phdr['IDCTAB']
-        except KeyError:
-            tddcorr = False
-            #print "***IDCTAB keyword not found - not applying TDD correction***\n"
-        if os.path.exists(fileutil.osfn(idctab)):
-            tddcorr = True
-        else:
-            tddcorr = False
-            #print "***IDCTAB file not found - not applying TDD correction***\n"
-    else:
-        tddcorr = False
-    return tddcorr
-
-def applyNpolCorr(fname, unpolcorr):
-    """
-    Determines whether non-polynomial distortion lookup tables should be added
-    as extensions to the science file based on the 'NPOLFILE' keyword in the
-    primary header and NPOLEXT kw in the first extension.
-    This is a default correction and will always run in the pipeline.
-    The file used to generate the extensions is
-    recorded in the NPOLEXT keyword in the first science extension.
-    If 'NPOLFILE' in the primary header is different from 'NPOLEXT' in the
-    extension header and the file exists on disk and is a 'new type' npolfile,
-    then the lookup tables will be updated as 'WCSDVARR' extensions.
-    """
-    applyNPOLCorr = True
-    try:
-        # get NPOLFILE kw from primary header
-        fnpol0 = fits.getval(fname, 'NPOLFILE')
-        if fnpol0 == 'N/A':
-            utils.remove_distortion(fname, "NPOLFILE")
-            return False
-        fnpol0 = fileutil.osfn(fnpol0)
-        if not fileutil.findFile(fnpol0):
-            msg =  """\n\tKw "NPOLFILE" exists in primary header but file %s not found
-                      Non-polynomial distortion correction will not be applied\n
-                    """ % fnpol0
-            logger.critical(msg)
-            raise IOError("NPOLFILE {0} not found".format(fnpol0))
-        try:
-            # get NPOLEXT kw from first extension header
-            fnpol1 = fits.getval(fname, 'NPOLEXT', ext=1)
-            fnpol1 = fileutil.osfn(fnpol1)
-            if fnpol1 and fileutil.findFile(fnpol1):
-                if fnpol0 != fnpol1:
-                    applyNPOLCorr = True
-                else:
-                    msg = """\n\tNPOLEXT with the same value as NPOLFILE found in first extension.
-                             NPOL correction will not be applied."""
-                    logger.info(msg)
-                    applyNPOLCorr = False
-            else:
-                # npl file defined in first extension may not be found
-                # but if a valid kw exists in the primary header, non-polynomial
-                #distortion correction should be applied.
-                applyNPOLCorr = True
-        except KeyError:
-            # the case of "NPOLFILE" kw present in primary header but "NPOLEXT" missing
-            # in first extension header
-            applyNPOLCorr = True
-    except KeyError:
-        logger.info('\n\t"NPOLFILE" keyword not found in primary header')
-        applyNPOLCorr = False
-        return applyNPOLCorr
-
-    if isOldStyleDGEO(fname, fnpol0):
-            applyNPOLCorr = False
-    return (applyNPOLCorr and unpolcorr)
-
-def isOldStyleDGEO(fname, dgname):
-    # checks if the file defined in a NPOLFILE kw is a full size
-    # (old style) image
-
-    sci_hdr = fits.getheader(fname, ext=1)
-    dgeo_hdr = fits.getheader(dgname, ext=1)
-    sci_naxis1 = sci_hdr['NAXIS1']
-    sci_naxis2 = sci_hdr['NAXIS2']
-    dg_naxis1 = dgeo_hdr['NAXIS1']
-    dg_naxis2 = dgeo_hdr['NAXIS2']
-    if sci_naxis1 <= dg_naxis1 or sci_naxis2 <= dg_naxis2:
-        msg = """\n\tOnly full size (old style) DGEO file was found.\n
-                 Non-polynomial distortion  correction will not be applied."""
-        logger.critical(msg)
-        return True
-    else:
-        return False
-
-def applyD2ImCorr(fname, d2imcorr):
-    applyD2IMCorr = True
-    try:
-        # get D2IMFILE kw from primary header
-        fd2im0 = fits.getval(fname, 'D2IMFILE')
-        if fd2im0 == 'N/A':
-            utils.remove_distortion(fname, "D2IMFILE")
-            return False
-        fd2im0 = fileutil.osfn(fd2im0)
-        if not fileutil.findFile(fd2im0):
-            msg = """\n\tKw D2IMFILE exists in primary header but file %s not found\n
-                     Detector to image correction will not be applied\n""" % fd2im0
-            logger.critical(msg)
-            print(msg)
-            raise IOError("D2IMFILE {0} not found".format(fd2im0))
-        try:
-            # get D2IMEXT kw from first extension header
-            fd2imext = fits.getval(fname, 'D2IMEXT', ext=1)
-            fd2imext = fileutil.osfn(fd2imext)
-            if fd2imext and fileutil.findFile(fd2imext):
-                if fd2im0 != fd2imext:
-                    applyD2IMCorr = True
-                else:
-                    applyD2IMCorr = False
-            else:
-                # D2IM file defined in first extension may not be found
-                # but if a valid kw exists in the primary header,
-                # detector to image correction should be applied.
-                applyD2IMCorr = True
-        except KeyError:
-            # the case of D2IMFILE kw present in primary header but D2IMEXT missing
-            # in first extension header
-            applyD2IMCorr = True
-    except KeyError:
-        print('D2IMFILE keyword not found in primary header')
-        applyD2IMCorr = False
-        return applyD2IMCorr
diff --git a/lib/stwcs/updatewcs/corrections.py b/lib/stwcs/updatewcs/corrections.py
deleted file mode 100644
index d3641eb..0000000
--- a/lib/stwcs/updatewcs/corrections.py
+++ /dev/null
@@ -1,326 +0,0 @@
-from __future__ import division, print_function # confidence high
-
-import copy
-import datetime
-import logging, time
-import numpy as np
-from numpy import linalg
-from stsci.tools import fileutil
-
-from . import npol
-from . import makewcs
-from .utils import diff_angles
-
-logger=logging.getLogger('stwcs.updatewcs.corrections')
-
-MakeWCS = makewcs.MakeWCS
-NPOLCorr = npol.NPOLCorr
-
-class TDDCorr(object):
-    """
-    Apply time dependent distortion correction to distortion coefficients and basic
-    WCS keywords. This correction **must** be done before any other WCS correction.
-
-    Parameters
-    ----------
-    ext_wcs: HSTWCS object
-             An HSTWCS object to be modified
-    ref_wcs: HSTWCS object
-             A reference HSTWCS object
-
-    Notes
-    -----
-    Compute the ACS/WFC time dependent distortion terms as described
-    in [1]_ and apply the correction to the WCS of the observation.
-
-    The model coefficients are stored in the primary header of the IDCTAB.
-    :math:`D_{ref}` is the reference date. The computed corrections are saved
-    in the science extension header as TDDALPHA and TDDBETA keywords.
-
-    .. math:: TDDALPHA = A_{0} + {A_{1}*(obsdate - D_{ref})}
-
-    .. math:: TDDBETA =  B_{0} + B_{1}*(obsdate - D_{ref})
-
-
-    The time dependent distortion affects the IDCTAB coefficients, and the
-    relative location of the two chips. Because the linear order IDCTAB
-    coefficients ar eused in the computatuion of the NPOL extensions,
-    the TDD correction affects all components of the distortion model.
-
-    Application of TDD to the IDCTAB polynomial coefficients:
-    The TDD model is computed in Jay's frame, while the IDCTAB coefficients
-    are in the HST V2/V3 frame. The coefficients are transformed to Jay's frame,
-    TDD is applied and they are transformed back to the V2/V3 frame. This
-    correction is performed in this class.
-
-    Application of TDD to the relative location of the two chips is
-    done in `makewcs`.
-
-    References
-    ----------
-    .. [1] Jay Anderson, "Variation of the Distortion Solution of the WFC", ACS ISR 2007-08.
-
-    """
-    def updateWCS(cls, ext_wcs, ref_wcs):
-        """
-        - Calculates alpha and beta for ACS/WFC data.
-        - Writes 2 new kw to the extension header: TDDALPHA and TDDBETA
-        """
-        logger.info("\n\tStarting TDDCorr: %s" % time.asctime())
-        ext_wcs.idcmodel.ocx = copy.deepcopy(ext_wcs.idcmodel.cx)
-        ext_wcs.idcmodel.ocy = copy.deepcopy(ext_wcs.idcmodel.cy)
-
-        newkw = {'TDDALPHA': None, 'TDDBETA':None,
-                'OCX10':ext_wcs.idcmodel.ocx[1,0],
-                'OCX11':ext_wcs.idcmodel.ocx[1,1],
-                'OCY10':ext_wcs.idcmodel.ocy[1,0],
-                'OCY11':ext_wcs.idcmodel.ocy[1,1],
-                'TDD_CTA':None, 'TDD_CTB':None,
-                'TDD_CYA':None, 'TDD_CYB':None,
-                'TDD_CXA':None, 'TDD_CXB':None}
-
-        if ext_wcs.idcmodel.refpix['skew_coeffs']is not None and \
-            ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CTB'] is not None:
-            cls.apply_tdd2idc2015(ref_wcs)
-            cls.apply_tdd2idc2015(ext_wcs)
-
-            newkw.update({
-                    'TDD_CTA':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CTA'],
-                    'TDD_CYA':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CYA'],
-                    'TDD_CXA':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CXA'],
-                    'TDD_CTB':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CTB'],
-                    'TDD_CYB':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CYB'],
-                    'TDD_CXB':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CXB']})
-
-        elif ext_wcs.idcmodel.refpix['skew_coeffs']is not None and \
-            ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CY_BETA'] is not None:
-            logger.info("\n\t Applying 2014-calibrated TDD: %s" % time.asctime())
-            # We have 2014-calibrated TDD, not J.A.-style TDD
-            cls.apply_tdd2idc2(ref_wcs)
-            cls.apply_tdd2idc2(ext_wcs)
-            newkw.update({'TDD_CYA':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CY_ALPHA'],
-                    'TDD_CYB':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CY_BETA'],
-                    'TDD_CXA':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CX_ALPHA'],
-                    'TDD_CXB':ext_wcs.idcmodel.refpix['skew_coeffs']['TDD_CX_BETA']})
-
-        else:
-            alpha, beta = cls.compute_alpha_beta(ext_wcs)
-            cls.apply_tdd2idc(ref_wcs, alpha, beta)
-            cls.apply_tdd2idc(ext_wcs, alpha, beta)
-            ext_wcs.idcmodel.refpix['TDDALPHA'] = alpha
-            ext_wcs.idcmodel.refpix['TDDBETA'] = beta
-            ref_wcs.idcmodel.refpix['TDDALPHA'] = alpha
-            ref_wcs.idcmodel.refpix['TDDBETA'] = beta
-
-            newkw.update( {'TDDALPHA': alpha, 'TDDBETA':beta} )
-
-        return newkw
-    updateWCS = classmethod(updateWCS)
-
-    def apply_tdd2idc2015(cls, hwcs):
-        """ Applies 2015-calibrated TDD correction to a couple of IDCTAB
-            coefficients for ACS/WFC observations.
-        """
-        if not isinstance(hwcs.date_obs,float):
-            year,month,day = hwcs.date_obs.split('-')
-            rdate = datetime.datetime(int(year),int(month),int(day))
-            rday = float(rdate.strftime("%j"))/365.25 + rdate.year
-        else:
-            rday = hwcs.date_obs
-
-        skew_coeffs = hwcs.idcmodel.refpix['skew_coeffs']
-        delta_date = rday - skew_coeffs['TDD_DATE']
-
-        if skew_coeffs['TDD_CXB'] is not None:
-            hwcs.idcmodel.cx[1,1] +=  skew_coeffs['TDD_CXB']*delta_date
-        if skew_coeffs['TDD_CTB'] is not None:
-            hwcs.idcmodel.cy[1,1] += skew_coeffs['TDD_CTB']*delta_date
-        if skew_coeffs['TDD_CYB'] is not None:
-            hwcs.idcmodel.cy[1,0] +=  skew_coeffs['TDD_CYB']*delta_date
-        #print("CX[1,1]_TDD={},  CY[1,1]_TDD={},  CY[1,0]_TDD={}".format(hwcs.idcmodel.cx[1,1],hwcs.idcmodel.cy[1,1],hwcs.idcmodel.cy[1,0]))
-
-    apply_tdd2idc2015 = classmethod(apply_tdd2idc2015)
-
-    def apply_tdd2idc2(cls, hwcs):
-        """ Applies 2014-calibrated TDD correction to single IDCTAB coefficient
-            of an ACS/WFC observation.
-        """
-        if not isinstance(hwcs.date_obs,float):
-            year,month,day = hwcs.date_obs.split('-')
-            rdate = datetime.datetime(int(year),int(month),int(day))
-            rday = float(rdate.strftime("%j"))/365.25 + rdate.year
-        else:
-            rday = hwcs.date_obs
-
-        skew_coeffs = hwcs.idcmodel.refpix['skew_coeffs']
-        cy_beta = skew_coeffs['TDD_CY_BETA']
-        cy_alpha = skew_coeffs['TDD_CY_ALPHA']
-        delta_date = rday - skew_coeffs['TDD_DATE']
-        print("DELTA_DATE: {0}   based on rday: {1}, TDD_DATE: {2}".format(delta_date,rday,skew_coeffs['TDD_DATE']))
-
-        if cy_alpha is None:
-            hwcs.idcmodel.cy[1,1] += cy_beta*delta_date
-        else:
-            new_beta = cy_alpha + cy_beta*delta_date
-            hwcs.idcmodel.cy[1,1] = new_beta
-        print("CY11: {0} based on alpha: {1}, beta: {2}".format(hwcs.idcmodel.cy[1,1],cy_alpha,cy_beta))
-
-        cx_beta = skew_coeffs['TDD_CX_BETA']
-        cx_alpha = skew_coeffs['TDD_CX_ALPHA']
-        if cx_alpha is not None:
-            new_beta = cx_alpha + cx_beta*delta_date
-            hwcs.idcmodel.cx[1,1] = new_beta
-            print("CX11: {0} based on alpha: {1}, beta: {2}".format(new_beta,cx_alpha,cx_beta))
-
-    apply_tdd2idc2 = classmethod(apply_tdd2idc2)
-
-    def apply_tdd2idc(cls, hwcs, alpha, beta):
-        """
-        Applies TDD to the idctab coefficients of a ACS/WFC observation.
-        This should be always the first correction.
-        """
-        theta_v2v3 = 2.234529
-        mrotp = fileutil.buildRotMatrix(theta_v2v3)
-        mrotn = fileutil.buildRotMatrix(-theta_v2v3)
-        tdd_mat = np.array([[1+(beta/2048.), alpha/2048.],[alpha/2048.,1-(beta/2048.)]],np.float64)
-        abmat1 = np.dot(tdd_mat, mrotn)
-        abmat2 = np.dot(mrotp,abmat1)
-        xshape, yshape = hwcs.idcmodel.cx.shape, hwcs.idcmodel.cy.shape
-        icxy = np.dot(abmat2,[hwcs.idcmodel.cx.ravel(), hwcs.idcmodel.cy.ravel()])
-        hwcs.idcmodel.cx = icxy[0]
-        hwcs.idcmodel.cy = icxy[1]
-        hwcs.idcmodel.cx.shape = xshape
-        hwcs.idcmodel.cy.shape = yshape
-
-    apply_tdd2idc = classmethod(apply_tdd2idc)
-
-    def compute_alpha_beta(cls, ext_wcs):
-        """
-        Compute the ACS time dependent distortion skew terms
-        as described in ACS ISR 07-08 by J. Anderson.
-
-        Jay's code only computes the alpha/beta values based on a decimal year
-        with only 3 digits, so this line reproduces that when needed for comparison
-        with his results.
-        rday = float(('%0.3f')%rday)
-
-        The zero-point terms account for the skew accumulated between
-        2002.0 and 2004.5, when the latest IDCTAB was delivered.
-        alpha = 0.095 + 0.090*(rday-dday)/2.5
-        beta = -0.029 - 0.030*(rday-dday)/2.5
-        """
-        if not isinstance(ext_wcs.date_obs,float):
-            year,month,day = ext_wcs.date_obs.split('-')
-            rdate = datetime.datetime(int(year),int(month),int(day))
-            rday = float(rdate.strftime("%j"))/365.25 + rdate.year
-        else:
-            rday = ext_wcs.date_obs
-
-        skew_coeffs = ext_wcs.idcmodel.refpix['skew_coeffs']
-        if skew_coeffs is None:
-            # Only print out warning for post-SM4 data where this may matter
-            if rday > 2009.0:
-                err_str =  "------------------------------------------------------------------------  \n"
-                err_str += "WARNING: the IDCTAB geometric distortion file specified in the image      \n"
-                err_str += "         header did not have the time-dependent distortion coefficients.  \n"
-                err_str += "         The pre-SM4 time-dependent skew solution will be used by default.\n"
-                err_str += "         Please update IDCTAB with new reference file from HST archive.   \n"
-                err_str +=  "------------------------------------------------------------------------  \n"
-                print(err_str)
-            # Using default pre-SM4 coefficients
-            skew_coeffs = {'TDD_A':[0.095,0.090/2.5],
-                        'TDD_B':[-0.029,-0.030/2.5],
-                        'TDD_DATE':2004.5,'TDDORDER':1}
-
-        alpha = 0
-        beta = 0
-        # Compute skew terms, allowing for non-linear coefficients as well
-        for c in range(skew_coeffs['TDDORDER']+1):
-            alpha += skew_coeffs['TDD_A'][c]* np.power((rday-skew_coeffs['TDD_DATE']),c)
-            beta += skew_coeffs['TDD_B'][c]*np.power((rday-skew_coeffs['TDD_DATE']),c)
-
-        return alpha,beta
-    compute_alpha_beta = classmethod(compute_alpha_beta)
-
-
-class VACorr(object):
-    """
-    Apply velocity aberation correction to WCS keywords.
-
-    Notes
-    -----
-    Velocity Aberration is stored in the extension header keyword 'VAFACTOR'.
-    The correction is applied to the CD matrix and CRVALs.
-
-    """
-    def updateWCS(cls, ext_wcs, ref_wcs):
-        logger.info("\n\tStarting VACorr: %s" % time.asctime())
-        if ext_wcs.vafactor != 1:
-            ext_wcs.wcs.cd = ext_wcs.wcs.cd * ext_wcs.vafactor
-            crval0 = ref_wcs.wcs.crval[0] + ext_wcs.vafactor*diff_angles(ext_wcs.wcs.crval[0],
-                                                                         ref_wcs.wcs.crval[0])
-            crval1 = ref_wcs.wcs.crval[1] + ext_wcs.vafactor*diff_angles(ext_wcs.wcs.crval[1],
-                                                                         ref_wcs.wcs.crval[1])
-            crval = np.array([crval0,crval1])
-            ext_wcs.wcs.crval = crval
-            ext_wcs.wcs.set()
-        else:
-            pass
-        kw2update={'CD1_1': ext_wcs.wcs.cd[0,0], 'CD1_2':ext_wcs.wcs.cd[0,1],
-                    'CD2_1':ext_wcs.wcs.cd[1,0], 'CD2_2':ext_wcs.wcs.cd[1,1],
-                    'CRVAL1':ext_wcs.wcs.crval[0], 'CRVAL2':ext_wcs.wcs.crval[1]}
-        return kw2update
-
-    updateWCS = classmethod(updateWCS)
-
-
-class CompSIP(object):
-    """
-    Compute Simple Imaging Polynomial (SIP) coefficients as defined in [2]_
-    from IDC table coefficients.
-
-    This class transforms the TDD corrected IDCTAB coefficients into SIP format.
-    It also applies a binning factor to the coefficients if the observation was
-    binned.
-
-    References
-    ----------
-    .. [2] David Shupe, et al, "The SIP Convention of representing Distortion
-       in FITS Image headers",  Astronomical Data Analysis Software And Systems, ASP
-       Conference Series, Vol. 347, 2005
-
-    """
-    def updateWCS(cls, ext_wcs, ref_wcs):
-        logger.info("\n\tStarting CompSIP: %s" %time.asctime())
-        kw2update = {}
-        if not ext_wcs.idcmodel:
-            logger.info("IDC model not found, SIP coefficient will not be computed")
-            return kw2update
-        order = ext_wcs.idcmodel.norder
-        kw2update['A_ORDER'] = order
-        kw2update['B_ORDER'] = order
-        pscale = ext_wcs.idcmodel.refpix['PSCALE']
-
-        cx = ext_wcs.idcmodel.cx
-        cy = ext_wcs.idcmodel.cy
-
-        matr = np.array([[cx[1,1],cx[1,0]], [cy[1,1],cy[1,0]]], dtype=np.float64)
-        imatr = linalg.inv(matr)
-        akeys1 = np.zeros((order+1,order+1), dtype=np.float64)
-        bkeys1 = np.zeros((order+1,order+1), dtype=np.float64)
-        for n in range(order+1):
-            for m in range(order+1):
-                if n >= m and n>=2:
-                    idcval = np.array([[cx[n,m]],[cy[n,m]]])
-                    sipval = np.dot(imatr, idcval)
-                    akeys1[m,n-m] = sipval[0]
-                    bkeys1[m,n-m] = sipval[1]
-                    Akey="A_%d_%d" % (m,n-m)
-                    Bkey="B_%d_%d" % (m,n-m)
-                    kw2update[Akey] = sipval[0,0] * ext_wcs.binned
-                    kw2update[Bkey] = sipval[1,0] * ext_wcs.binned
-        kw2update['CTYPE1'] = 'RA---TAN-SIP'
-        kw2update['CTYPE2'] = 'DEC--TAN-SIP'
-        return kw2update
-
-    updateWCS = classmethod(updateWCS)
diff --git a/lib/stwcs/updatewcs/det2im.py b/lib/stwcs/updatewcs/det2im.py
deleted file mode 100644
index bddb37b..0000000
--- a/lib/stwcs/updatewcs/det2im.py
+++ /dev/null
@@ -1,299 +0,0 @@
-from __future__ import absolute_import, division # confidence high
-
-import numpy as np
-from astropy.io import fits
-from stsci.tools import fileutil
-
-from . import utils
-
-import logging, time
-logger = logging.getLogger('stwcs.updatewcs.d2im')
-
-class DET2IMCorr(object):
-    """
-    Defines a Lookup table prior distortion correction as per WCS paper IV.
-    It uses a reference file defined by the D2IMFILE (suffix 'd2im') keyword
-    in the primary header.
-
-    Notes
-    -----
-    - Using extensions in the reference file create a WCSDVARR extensions
-      and add them to the science file.
-    - Add record-valued keywords to the science extension header to describe
-      the lookup tables.
-    - Add a keyword 'D2IMEXT' to the science extension header to store
-      the name of the reference file used to create the WCSDVARR extensions.
-
-    If WCSDVARR extensions exist and `D2IMFILE` is different from `D2IMEXT`,
-    a subsequent update will overwrite the existing extensions.
-    If WCSDVARR extensions were not found in the science file, they will be added.
-
-    """
-
-    def updateWCS(cls, fobj):
-        """
-        Parameters
-        ----------
-        fobj: `astropy.io.fits.HDUList` object
-                Science file, for which a distortion correction in a NPOLFILE is available
-
-        """
-        logger.info("\n\tStarting DET2IM: %s" %time.asctime())
-        try:
-            assert isinstance(fobj, fits.HDUList)
-        except AssertionError:
-            logger.exception('\n\tInput must be a fits.HDUList object')
-            raise
-
-        cls.applyDet2ImCorr(fobj)
-        d2imfile = fobj[0].header['D2IMFILE']
-
-        new_kw = {'D2IMEXT': d2imfile}
-        return new_kw
-
-    updateWCS = classmethod(updateWCS)
-
-    def applyDet2ImCorr(cls, fobj):
-        """
-        For each science extension in a fits file object:
-            - create a WCSDVARR extension
-            - update science header
-            - add/update D2IMEXT keyword
-        """
-        d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE'])
-        # Map D2IMARR EXTVER numbers to FITS extension numbers
-        wcsdvarr_ind = cls.getWCSIndex(fobj)
-        d2im_num_ext = 1
-        for ext in fobj:
-            try:
-                extname = ext.header['EXTNAME'].lower()
-            except KeyError:
-                continue
-            if extname == 'sci':
-                extversion = ext.header['EXTVER']
-                ccdchip = cls.get_ccdchip(fobj, extname='SCI', extver=extversion)
-                header = ext.header
-                # get the data arrays from the reference file
-                dx, dy = cls.getData(d2imfile, ccdchip)
-                # Determine EXTVER for the D2IMARR extension from the D2I file (EXTNAME, EXTVER) kw.
-                # This is used to populate DPj.EXTVER kw
-                for ename in zip(['DX', 'DY'], [dx, dy]):
-                    if ename[1] is not None:
-                        error_val = ename[1].max()
-                        cls.addSciExtKw(header, wdvarr_ver=d2im_num_ext, d2im_extname=ename[0], error_val=error_val)
-                        hdu = cls.createD2ImHDU(header, d2imfile=d2imfile,
-                                                wdvarr_ver=d2im_num_ext,
-                                                d2im_extname=ename[0],
-                                                data=ename[1],ccdchip=ccdchip)
-                        if wcsdvarr_ind and d2im_num_ext in wcsdvarr_ind:
-                            fobj[wcsdvarr_ind[d2im_num_ext]] = hdu
-                        else:
-                            fobj.append(hdu)
-                        d2im_num_ext = d2im_num_ext + 1
-    applyDet2ImCorr = classmethod(applyDet2ImCorr)
-
-    def getWCSIndex(cls, fobj):
-
-        """
-        If fobj has WCSDVARR extensions:
-            returns a mapping of their EXTVER kw to file object extension numbers
-        if fobj does not have WCSDVARR extensions:
-            an empty dictionary is returned
-        """
-        wcsd = {}
-        for e in range(len(fobj)):
-            try:
-                ename = fobj[e].header['EXTNAME']
-            except KeyError:
-                continue
-            if ename == 'D2IMARR':
-                wcsd[fobj[e].header['EXTVER']] = e
-        logger.debug("A map of D2IMARR extensions %s" % wcsd)
-        return wcsd
-
-    getWCSIndex = classmethod(getWCSIndex)
-
-    def addSciExtKw(cls, hdr, wdvarr_ver=None, d2im_extname=None, error_val=0.0):
-        """
-        Adds kw to sci extension to define WCSDVARR lookup table extensions
-
-        """
-        if d2im_extname =='DX':
-            j=1
-        else:
-            j=2
-
-        d2imerror = 'D2IMERR%s' %j
-        d2imdis = 'D2IMDIS%s' %j
-        d2imext = 'D2IM%s.' %j + 'EXTVER'
-        d2imnaxes = 'D2IM%s.' %j +'NAXES'
-        d2imaxis1 = 'D2IM%s.' %j+'AXIS.1'
-        d2imaxis2 = 'D2IM%s.' %j+'AXIS.2'
-        keys = [d2imerror, d2imdis, d2imext, d2imnaxes, d2imaxis1, d2imaxis2]
-        values = {d2imerror: error_val,
-                  d2imdis: 'Lookup',
-                  d2imext: wdvarr_ver,
-                  d2imnaxes: 2,
-                  d2imaxis1: 1,
-                  d2imaxis2: 2}
-
-        comments = {d2imerror: 'Maximum error of NPOL correction for axis %s' % j,
-                    d2imdis: 'Detector to image correction type',
-                    d2imext: 'Version number of WCSDVARR extension containing d2im lookup table',
-                    d2imnaxes: 'Number of independent variables in d2im function',
-                    d2imaxis1: 'Axis number of the jth independent variable in a d2im function',
-                    d2imaxis2: 'Axis number of the jth independent variable in a d2im function'
-                    }
-        # Look for HISTORY keywords. If present, insert new keywords before them
-        before_key = 'HISTORY'
-        if before_key not in hdr:
-            before_key = None
-
-        for key in keys:
-            hdr.set(key, value=values[key], comment=comments[key], before=before_key)
-
-    addSciExtKw = classmethod(addSciExtKw)
-
-    def getData(cls,d2imfile, ccdchip):
-        """
-        Get the data arrays from the reference D2I files
-        Make sure 'CCDCHIP' in the npolfile matches "CCDCHIP' in the science file.
-        """
-        xdata, ydata = (None, None)
-        d2im = fits.open(d2imfile)
-        for ext in d2im:
-            d2imextname  = ext.header.get('EXTNAME',"")
-            d2imccdchip  = ext.header.get('CCDCHIP',1)
-            if d2imextname == 'DX' and d2imccdchip == ccdchip:
-                xdata = ext.data.copy()
-                continue
-            elif d2imextname == 'DY' and d2imccdchip == ccdchip:
-                ydata = ext.data.copy()
-                continue
-            else:
-                continue
-        d2im.close()
-        return xdata, ydata
-    getData = classmethod(getData)
-
-    def createD2ImHDU(cls, sciheader, d2imfile=None, wdvarr_ver=1,
-                      d2im_extname=None,data = None, ccdchip=1):
-        """
-        Creates an HDU to be added to the file object.
-        """
-        hdr = cls.createD2ImHdr(sciheader, d2imfile=d2imfile,
-                                wdvarr_ver=wdvarr_ver, d2im_extname=d2im_extname,
-                                ccdchip=ccdchip)
-        hdu = fits.ImageHDU(header=hdr, data=data)
-        return hdu
-
-    createD2ImHDU = classmethod(createD2ImHDU)
-
-    def createD2ImHdr(cls, sciheader, d2imfile, wdvarr_ver, d2im_extname, ccdchip):
-        """
-        Creates a header for the D2IMARR extension based on the D2I reference file
-        and sci extension header. The goal is to always work in image coordinates
-        (also for subarrays and binned images). The WCS for the D2IMARR extension
-        is such that a full size d2im table is created and then shifted or scaled
-        if the science image is a subarray or binned image.
-        """
-        d2im = fits.open(d2imfile)
-        d2im_phdr = d2im[0].header
-        for ext in d2im:
-            try:
-                d2imextname = ext.header['EXTNAME']
-                d2imextver = ext.header['EXTVER']
-            except KeyError:
-                continue
-            d2imccdchip = cls.get_ccdchip(d2im, extname=d2imextname, extver=d2imextver)
-            if d2imextname == d2im_extname and d2imccdchip == ccdchip:
-                d2im_header = ext.header
-                break
-            else:
-                continue
-        d2im.close()
-
-        naxis = d2im[1].header['NAXIS']
-        ccdchip = d2imextname
-
-        kw = { 'NAXIS': 'Size of the axis',
-               'CDELT': 'Coordinate increment along axis',
-               'CRPIX': 'Coordinate system reference pixel',
-               'CRVAL': 'Coordinate system value at reference pixel',
-               }
-
-        kw_comm1 = {}
-        kw_val1 = {}
-        for key in kw.keys():
-            for i in range(1, naxis+1):
-                si = str(i)
-                kw_comm1[key+si] = kw[key]
-
-        for i in range(1, naxis+1):
-            si = str(i)
-            kw_val1['NAXIS'+si] = d2im_header.get('NAXIS'+si)
-            kw_val1['CDELT'+si] = d2im_header.get('CDELT'+si, 1.0) * sciheader.get('LTM'+si+'_'+si, 1)
-            kw_val1['CRPIX'+si] = d2im_header.get('CRPIX'+si, 0.0)
-            kw_val1['CRVAL'+si] = (d2im_header.get('CRVAL'+si, 0.0) - \
-                                   sciheader.get('LTV'+str(i), 0))
-        kw_comm0 = {'XTENSION': 'Image extension',
-                    'BITPIX': 'IEEE floating point',
-                    'NAXIS': 'Number of axes',
-                    'EXTNAME': 'WCS distortion array',
-                    'EXTVER': 'Distortion array version number',
-                    'PCOUNT': 'Special data area of size 0',
-                    'GCOUNT': 'One data group',
-                    }
-
-        kw_val0 = { 'XTENSION': 'IMAGE',
-                    'BITPIX': -32,
-                    'NAXIS': naxis,
-                    'EXTNAME': 'D2IMARR',
-                    'EXTVER':  wdvarr_ver,
-                    'PCOUNT': 0,
-                    'GCOUNT': 1,
-                    'CCDCHIP': ccdchip,
-                }
-        cdl = []
-        for key in kw_comm0.keys():
-            cdl.append((key, kw_val0[key], kw_comm0[key]))
-        for key in kw_comm1.keys():
-            cdl.append((key, kw_val1[key], kw_comm1[key]))
-        # Now add keywords from NPOLFILE header to document source of calibration
-        # include all keywords after and including 'FILENAME' from header
-        start_indx = -1
-        end_indx = 0
-        for i, c in enumerate(d2im_phdr):
-            if c == 'FILENAME':
-                start_indx = i
-            if c == '': # remove blanks from end of header
-                end_indx = i+1
-                break
-        if start_indx >= 0:
-            for card in d2im_phdr.cards[start_indx:end_indx]:
-                cdl.append(card)
-
-        hdr = fits.Header(cards=cdl)
-
-        return hdr
-
-    createD2ImHdr = classmethod(createD2ImHdr)
-
-    def get_ccdchip(cls, fobj, extname, extver):
-        """
-        Given a science file or npol file determine CCDCHIP
-        """
-        ccdchip = 1
-        if fobj[0].header['INSTRUME'] == 'ACS' and fobj[0].header['DETECTOR'] == 'WFC':
-            ccdchip = fobj[extname, extver].header['CCDCHIP']
-        elif fobj[0].header['INSTRUME'] == 'WFC3' and fobj[0].header['DETECTOR'] == 'UVIS':
-            ccdchip =  fobj[extname, extver].header['CCDCHIP']
-        elif fobj[0].header['INSTRUME'] == 'WFPC2':
-            ccdchip = fobj[extname, extver].header['DETECTOR']
-        elif fobj[0].header['INSTRUME'] == 'STIS':
-            ccdchip = fobj[extname, extver].header['DETECTOR']
-        elif fobj[0].header['INSTRUME'] == 'NICMOS':
-            ccdchip = fobj[extname, extver].header['CAMERA']
-        return ccdchip
-
-    get_ccdchip = classmethod(get_ccdchip)
diff --git a/lib/stwcs/updatewcs/makewcs.py b/lib/stwcs/updatewcs/makewcs.py
deleted file mode 100644
index 06c6f9c..0000000
--- a/lib/stwcs/updatewcs/makewcs.py
+++ /dev/null
@@ -1,273 +0,0 @@
-from __future__ import absolute_import, division # confidence high
-
-import datetime
-
-import numpy as np
-import logging, time
-from math import sin, sqrt, pow, cos, asin, atan2,pi
-
-from stsci.tools import fileutil
-from . import utils
-
-logger = logging.getLogger(__name__)
-
-class MakeWCS(object):
-    """
-    Recompute basic WCS keywords based on PA_V3 and distortion model.
-
-    Notes
-    -----
-    - Compute the reference chip WCS:
-
-        -- CRVAL: transform the model XREF/YREF to the sky
-        -- PA_V3 is calculated at the target position and adjusted
-           for each chip orientation
-        -- CD: PA_V3 and the model scale are used to cnstruct a CD matrix
-
-    - Compute the second chip WCS:
-
-        -- CRVAL: - the distance between the zero points of the two
-                  chip models on the sky
-        -- CD matrix: first order coefficients are added to the components
-            of this distance and transfered on the sky. The difference
-            between CRVAL and these vectors is the new CD matrix for each chip.
-        -- CRPIX: chip's model zero point in pixel space (XREF/YREF)
-
-    - Time dependent distortion correction is applied to both chips' V2/V3 values.
-
-    """
-    tdd_xyref = {1: [2048, 3072], 2:[2048, 1024]}
-    def updateWCS(cls, ext_wcs, ref_wcs):
-        """
-        recomputes the basic WCS kw
-        """
-        logger.info("\n\tStarting MakeWCS: %s" % time.asctime())
-        if not ext_wcs.idcmodel:
-            logger.info("IDC model not found, turning off Makewcs")
-            return {}
-        ltvoff, offshift = cls.getOffsets(ext_wcs)
-
-        v23_corr = cls.zero_point_corr(ext_wcs)
-        rv23_corr = cls.zero_point_corr(ref_wcs)
-
-        cls.uprefwcs(ext_wcs, ref_wcs, rv23_corr, ltvoff, offshift)
-        cls.upextwcs(ext_wcs, ref_wcs, v23_corr, rv23_corr, ltvoff, offshift)
-
-        kw2update = {'CD1_1': ext_wcs.wcs.cd[0,0],
-                    'CD1_2': ext_wcs.wcs.cd[0,1],
-                    'CD2_1': ext_wcs.wcs.cd[1,0],
-                    'CD2_2': ext_wcs.wcs.cd[1,1],
-                    'CRVAL1': ext_wcs.wcs.crval[0],
-                    'CRVAL2': ext_wcs.wcs.crval[1],
-                    'CRPIX1': ext_wcs.wcs.crpix[0],
-                    'CRPIX2': ext_wcs.wcs.crpix[1],
-                    'IDCTAB': ext_wcs.idctab,
-                    'OCX10' : ext_wcs.idcmodel.cx[1,0],
-                    'OCX11' : ext_wcs.idcmodel.cx[1,1],
-                    'OCY10' : ext_wcs.idcmodel.cy[1,0],
-                    'OCY11' : ext_wcs.idcmodel.cy[1,1]
-            }
-        return kw2update
-
-    updateWCS = classmethod(updateWCS)
-
-    def upextwcs(cls, ext_wcs, ref_wcs, v23_corr, rv23_corr, loff, offsh):
-        """
-        updates an extension wcs
-        """
-        ltvoffx, ltvoffy = loff[0], loff[1]
-        offshiftx, offshifty = offsh[0], offsh[1]
-        ltv1 = ext_wcs.ltv1
-        ltv2 = ext_wcs.ltv2
-        if ltv1 != 0. or ltv2 != 0.:
-            offsetx = ext_wcs.wcs.crpix[0] - ltv1 - ext_wcs.idcmodel.refpix['XREF']
-            offsety = ext_wcs.wcs.crpix[1] - ltv2 - ext_wcs.idcmodel.refpix['YREF']
-            ext_wcs.idcmodel.shift(offsetx,offsety)
-
-        fx, fy = ext_wcs.idcmodel.cx, ext_wcs.idcmodel.cy
-
-        ext_wcs.setPscale()
-        tddscale = (ref_wcs.pscale/fx[1,1])
-        v2 = ext_wcs.idcmodel.refpix['V2REF'] + v23_corr[0,0] * tddscale
-        v3 = ext_wcs.idcmodel.refpix['V3REF'] - v23_corr[1,0] * tddscale
-        v2ref = ref_wcs.idcmodel.refpix['V2REF'] + rv23_corr[0,0] * tddscale
-        v3ref = ref_wcs.idcmodel.refpix['V3REF'] - rv23_corr[1,0] * tddscale
-
-        R_scale = ref_wcs.idcmodel.refpix['PSCALE']/3600.0
-        off = sqrt((v2-v2ref)**2 + (v3-v3ref)**2)/(R_scale*3600.0)
-
-        if v3 == v3ref:
-            theta=0.0
-        else:
-            theta = atan2(ext_wcs.parity[0][0]*(v2-v2ref), ext_wcs.parity[1][1]*(v3-v3ref))
-
-        if ref_wcs.idcmodel.refpix['THETA']: theta += ref_wcs.idcmodel.refpix['THETA']*pi/180.0
-
-        dX=(off*sin(theta)) + offshiftx
-        dY=(off*cos(theta)) + offshifty
-
-        px = np.array([[dX,dY]])
-        newcrval = ref_wcs.wcs.p2s(px, 1)['world'][0]
-        newcrpix = np.array([ext_wcs.idcmodel.refpix['XREF'] + ltvoffx,
-                                ext_wcs.idcmodel.refpix['YREF'] + ltvoffy])
-        ext_wcs.wcs.crval = newcrval
-        ext_wcs.wcs.crpix = newcrpix
-        ext_wcs.wcs.set()
-
-        # Create a small vector, in reference image pixel scale
-        delmat = np.array([[fx[1,1], fy[1,1]], \
-                              [fx[1,0], fy[1,0]]]) / R_scale/3600.
-
-        # Account for subarray offset
-        # Angle of chip relative to chip
-        if ext_wcs.idcmodel.refpix['THETA']:
-            dtheta = ext_wcs.idcmodel.refpix['THETA'] - ref_wcs.idcmodel.refpix['THETA']
-        else:
-            dtheta = 0.0
-
-        rrmat = fileutil.buildRotMatrix(dtheta)
-        # Rotate the vectors
-        dxy = np.dot(delmat, rrmat)
-        wc = ref_wcs.wcs.p2s((px + dxy), 1)['world']
-
-        # Calculate the new CDs and convert to degrees
-        cd11 = utils.diff_angles(wc[0,0],newcrval[0])*cos(newcrval[1]*pi/180.0)
-        cd12 = utils.diff_angles(wc[1,0],newcrval[0])*cos(newcrval[1]*pi/180.0)
-        cd21 = utils.diff_angles(wc[0,1],newcrval[1])
-        cd22 = utils.diff_angles(wc[1,1],newcrval[1])
-        cd = np.array([[cd11, cd12], [cd21, cd22]])
-        ext_wcs.wcs.cd = cd
-        ext_wcs.wcs.set()
-
-    upextwcs = classmethod(upextwcs)
-
-    def uprefwcs(cls, ext_wcs, ref_wcs, rv23_corr_tdd, loff, offsh):
-        """
-        Updates the reference chip
-        """
-        ltvoffx, ltvoffy = loff[0], loff[1]
-        ltv1 = ref_wcs.ltv1
-        ltv2 = ref_wcs.ltv2
-        if ref_wcs.ltv1 != 0. or ref_wcs.ltv2 != 0.:
-            offsetx = ref_wcs.wcs.crpix[0] - ltv1 - ref_wcs.idcmodel.refpix['XREF']
-            offsety = ref_wcs.wcs.crpix[1] - ltv2 - ref_wcs.idcmodel.refpix['YREF']
-            ref_wcs.idcmodel.shift(offsetx,offsety)
-
-        rfx, rfy = ref_wcs.idcmodel.cx, ref_wcs.idcmodel.cy
-
-        offshift = offsh
-        dec = ref_wcs.wcs.crval[1]
-        tddscale = (ref_wcs.pscale/ref_wcs.idcmodel.cx[1,1])
-        rv23 = [ref_wcs.idcmodel.refpix['V2REF'] + (rv23_corr_tdd[0,0] *tddscale),
-            ref_wcs.idcmodel.refpix['V3REF'] - (rv23_corr_tdd[1,0] * tddscale)]
-        # Get an approximate reference position on the sky
-        rref = np.array([[ref_wcs.idcmodel.refpix['XREF']+ltvoffx ,
-                            ref_wcs.idcmodel.refpix['YREF']+ltvoffy]])
-
-        crval = ref_wcs.wcs.p2s(rref, 1)['world'][0]
-        # Convert the PA_V3 orientation to the orientation at the aperture
-        # This is for the reference chip only - we use this for the
-        # reference tangent plane definition
-        # It has the same orientation as the reference chip
-        pv = troll(ext_wcs.pav3,dec,rv23[0], rv23[1])
-        # Add the chip rotation angle
-        if ref_wcs.idcmodel.refpix['THETA']:
-            pv += ref_wcs.idcmodel.refpix['THETA']
-
-
-        # Set values for the rest of the reference WCS
-        ref_wcs.wcs.crval = crval
-        ref_wcs.wcs.crpix = np.array([0.0,0.0])+offsh
-        parity = ref_wcs.parity
-        R_scale = ref_wcs.idcmodel.refpix['PSCALE']/3600.0
-        cd11 = parity[0][0] *  cos(pv*pi/180.0)*R_scale
-        cd12 = parity[0][0] * -sin(pv*pi/180.0)*R_scale
-        cd21 = parity[1][1] *  sin(pv*pi/180.0)*R_scale
-        cd22 = parity[1][1] *  cos(pv*pi/180.0)*R_scale
-
-        rcd = np.array([[cd11, cd12], [cd21, cd22]])
-        ref_wcs.wcs.cd = rcd
-        ref_wcs.wcs.set()
-
-    uprefwcs = classmethod(uprefwcs)
-
-    def zero_point_corr(cls,hwcs):
-        if hwcs.idcmodel.refpix['skew_coeffs'] is not None and 'TDD_CY_BETA' in hwcs.idcmodel.refpix['skew_coeffs']:
-            v23_corr = np.array([[0.],[0.]])
-            return v23_corr
-        else:
-            try:
-                alpha = hwcs.idcmodel.refpix['TDDALPHA']
-                beta = hwcs.idcmodel.refpix['TDDBETA']
-            except KeyError:
-                alpha = 0.0
-                beta = 0.0
-                v23_corr = np.array([[0.],[0.]])
-                logger.debug("\n\tTDD Zero point correction for chip %s defaulted to: %s" % (hwcs.chip, v23_corr))
-                return v23_corr
-
-        tdd = np.array([[beta, alpha], [alpha, -beta]])
-        mrotp = fileutil.buildRotMatrix(2.234529)/2048.
-        xy0 = np.array([[cls.tdd_xyref[hwcs.chip][0]-2048.], [cls.tdd_xyref[hwcs.chip][1]-2048.]])
-        v23_corr = np.dot(mrotp,np.dot(tdd,xy0)) * 0.05
-        logger.debug("\n\tTDD Zero point correction for chip %s: %s" % (hwcs.chip, v23_corr))
-        return v23_corr
-
-    zero_point_corr = classmethod(zero_point_corr)
-
-    def getOffsets(cls, ext_wcs):
-        ltv1 = ext_wcs.ltv1
-        ltv2 = ext_wcs.ltv2
-
-        offsetx = ext_wcs.wcs.crpix[0] - ltv1 - ext_wcs.idcmodel.refpix['XREF']
-        offsety = ext_wcs.wcs.crpix[1] - ltv2 - ext_wcs.idcmodel.refpix['YREF']
-
-        shiftx = ext_wcs.idcmodel.refpix['XREF'] + ltv1
-        shifty = ext_wcs.idcmodel.refpix['YREF'] + ltv2
-        if ltv1 != 0. or ltv2 != 0.:
-            ltvoffx = ltv1 + offsetx
-            ltvoffy = ltv2 + offsety
-            offshiftx = offsetx + shiftx
-            offshifty = offsety + shifty
-        else:
-            ltvoffx = 0.
-            ltvoffy = 0.
-            offshiftx = 0.
-            offshifty = 0.
-
-        ltvoff = np.array([ltvoffx, ltvoffy])
-        offshift = np.array([offshiftx, offshifty])
-        return ltvoff, offshift
-
-    getOffsets = classmethod(getOffsets)
-
-
-def troll(roll, dec, v2, v3):
-    """ Computes the roll angle at the target position based on:
-        the roll angle at the V1 axis(roll),
-        the dec of the target(dec), and
-        the V2/V3 position of the aperture (v2,v3) in arcseconds.
-
-        Based on algorithm provided by Colin Cox and used in
-        Generic Conversion at STScI.
-    """
-    # Convert all angles to radians
-    _roll = np.deg2rad(roll)
-    _dec = np.deg2rad(dec)
-    _v2 = np.deg2rad(v2 / 3600.)
-    _v3 = np.deg2rad(v3 / 3600.)
-
-    # compute components
-    sin_rho = sqrt((pow(sin(_v2),2)+pow(sin(_v3),2)) - (pow(sin(_v2),2)*pow(sin(_v3),2)))
-    rho = asin(sin_rho)
-    beta = asin(sin(_v3)/sin_rho)
-    if _v2 < 0: beta = pi - beta
-    gamma = asin(sin(_v2)/sin_rho)
-    if _v3 < 0: gamma = pi - gamma
-    A = pi/2. + _roll - beta
-    B = atan2( sin(A)*cos(_dec), (sin(_dec)*sin_rho - cos(_dec)*cos(rho)*cos(A)))
-
-    # compute final value
-    troll = np.rad2deg(pi - (gamma+B))
-
-    return troll
diff --git a/lib/stwcs/updatewcs/npol.py b/lib/stwcs/updatewcs/npol.py
deleted file mode 100644
index 33579f0..0000000
--- a/lib/stwcs/updatewcs/npol.py
+++ /dev/null
@@ -1,343 +0,0 @@
-from __future__ import absolute_import, division # confidence high
-
-import logging, time
-
-import numpy as np
-from astropy.io import fits
-
-from stsci.tools import fileutil
-from . import utils
-
-logger = logging.getLogger('stwcs.updatewcs.npol')
-
-class NPOLCorr(object):
-    """
-    Defines a Lookup table prior distortion correction as per WCS paper IV.
-    It uses a reference file defined by the NPOLFILE (suffix 'NPL') keyword
-    in the primary header.
-
-    Notes
-    -----
-    - Using extensions in the reference file create a WCSDVARR extensions
-      and add them to the science file.
-    - Add record-valued keywords to the science extension header to describe
-      the lookup tables.
-    - Add a keyword 'NPOLEXT' to the science extension header to store
-      the name of the reference file used to create the WCSDVARR extensions.
-
-    If WCSDVARR extensions exist and `NPOLFILE` is different from `NPOLEXT`,
-    a subsequent update will overwrite the existing extensions.
-    If WCSDVARR extensions were not found in the science file, they will be added.
-
-    It is assumed that the NPL reference files were created to work with IDC tables
-    but will be applied with SIP coefficients. A transformation is applied to correct
-    for the fact that the lookup tables will be applied before the first order coefficients
-    which are in the CD matrix when the SIP convention is used.
-    """
-
-    def updateWCS(cls, fobj):
-        """
-        Parameters
-        ----------
-        fobj : `astropy.io.fits.HDUList` object
-            Science file, for which a distortion correction in a NPOLFILE is available
-
-        """
-        logger.info("\n\tStarting NPOL: %s" %time.asctime())
-        try:
-            assert isinstance(fobj, fits.HDUList)
-        except AssertionError:
-            logger.exception('\n\tInput must be a fits.HDUList object')
-            raise
-
-        cls.applyNPOLCorr(fobj)
-        nplfile = fobj[0].header['NPOLFILE']
-
-        new_kw = {'NPOLEXT': nplfile}
-        return new_kw
-
-    updateWCS = classmethod(updateWCS)
-
-    def applyNPOLCorr(cls, fobj):
-        """
-        For each science extension in a fits file object:
-            - create a WCSDVARR extension
-            - update science header
-            - add/update NPOLEXT keyword
-        """
-        nplfile = fileutil.osfn(fobj[0].header['NPOLFILE'])
-        # Map WCSDVARR EXTVER numbers to extension numbers
-        wcsdvarr_ind = cls.getWCSIndex(fobj)
-        for ext in fobj:
-            try:
-                extname = ext.header['EXTNAME'].lower()
-            except KeyError:
-                continue
-            if extname == 'sci':
-                extversion = ext.header['EXTVER']
-                ccdchip = cls.get_ccdchip(fobj, extname='SCI', extver=extversion)
-                header = ext.header
-                # get the data arrays from the reference file and transform
-                # them for use with SIP
-                dx,dy = cls.getData(nplfile, ccdchip)
-                idccoeffs = cls.getIDCCoeffs(header)
-
-                if idccoeffs is not None:
-                    dx, dy = cls.transformData(dx,dy, idccoeffs)
-
-                # Determine EXTVER for the WCSDVARR extension from the
-                # NPL file (EXTNAME, EXTVER) kw.
-                # This is used to populate DPj.EXTVER kw
-                wcsdvarr_x_version = 2 * extversion -1
-                wcsdvarr_y_version = 2 * extversion
-                for ename in zip(['DX', 'DY'], [wcsdvarr_x_version,wcsdvarr_y_version],[dx, dy]):
-                    error_val = ename[2].max()
-                    cls.addSciExtKw(header, wdvarr_ver=ename[1], npol_extname=ename[0], error_val=error_val)
-                    hdu = cls.createNpolHDU(header, npolfile=nplfile, \
-                        wdvarr_ver=ename[1], npl_extname=ename[0], data=ename[2],ccdchip=ccdchip)
-                    if wcsdvarr_ind:
-                        fobj[wcsdvarr_ind[ename[1]]] = hdu
-                    else:
-                        fobj.append(hdu)
-
-
-    applyNPOLCorr = classmethod(applyNPOLCorr)
-
-    def getWCSIndex(cls, fobj):
-
-        """
-        If fobj has WCSDVARR extensions:
-            returns a mapping of their EXTVER kw to file object extension numbers
-        if fobj does not have WCSDVARR extensions:
-            an empty dictionary is returned
-        """
-        wcsd = {}
-        for e in range(len(fobj)):
-            try:
-                ename = fobj[e].header['EXTNAME']
-            except KeyError:
-                continue
-            if ename == 'WCSDVARR':
-                wcsd[fobj[e].header['EXTVER']] = e
-        logger.debug("A map of WSCDVARR externsions %s" % wcsd)
-        return wcsd
-
-    getWCSIndex = classmethod(getWCSIndex)
-
-    def addSciExtKw(cls, hdr, wdvarr_ver=None, npol_extname=None, error_val=0.0):
-        """
-        Adds kw to sci extension to define WCSDVARR lookup table extensions
-
-        """
-        if npol_extname =='DX':
-            j=1
-        else:
-            j=2
-
-        cperror = 'CPERR%s' %j
-        cpdis = 'CPDIS%s' %j
-        dpext = 'DP%s.' %j + 'EXTVER'
-        dpnaxes = 'DP%s.' %j +'NAXES'
-        dpaxis1 = 'DP%s.' %j+'AXIS.1'
-        dpaxis2 = 'DP%s.' %j+'AXIS.2'
-        keys = [cperror, cpdis, dpext, dpnaxes, dpaxis1, dpaxis2]
-        values = {cperror: error_val,
-                  cpdis: 'Lookup',
-                  dpext: wdvarr_ver,
-                  dpnaxes: 2,
-                  dpaxis1: 1,
-                  dpaxis2: 2}
-
-        comments = {cperror: 'Maximum error of NPOL correction for axis %s' % j,
-                    cpdis: 'Prior distortion function type',
-                    dpext: 'Version number of WCSDVARR extension containing lookup distortion table',
-                    dpnaxes: 'Number of independent variables in distortion function',
-                    dpaxis1: 'Axis number of the jth independent variable in a distortion function',
-                    dpaxis2: 'Axis number of the jth independent variable in a distortion function'
-                    }
-        # Look for HISTORY keywords. If present, insert new keywords before them
-        before_key = 'HISTORY'
-        if before_key not in hdr:
-            before_key = None
-
-        for key in keys:
-            hdr.set(key, value=values[key], comment=comments[key], before=before_key)
-
-    addSciExtKw = classmethod(addSciExtKw)
-
-    def getData(cls,nplfile, ccdchip):
-        """
-        Get the data arrays from the reference NPOL files
-        Make sure 'CCDCHIP' in the npolfile matches "CCDCHIP' in the science file.
-        """
-        npl = fits.open(nplfile)
-        for ext in npl:
-            nplextname  = ext.header.get('EXTNAME',"")
-            nplccdchip  = ext.header.get('CCDCHIP',1)
-            if nplextname == 'DX' and nplccdchip == ccdchip:
-                xdata = ext.data.copy()
-                continue
-            elif nplextname == 'DY' and nplccdchip == ccdchip:
-                ydata = ext.data.copy()
-                continue
-            else:
-                continue
-        npl.close()
-        return xdata, ydata
-    getData = classmethod(getData)
-
-    def transformData(cls, dx, dy, coeffs):
-        """
-        Transform the NPOL data arrays for use with SIP
-        """
-        ndx, ndy = np.dot(coeffs, [dx.ravel(), dy.ravel()]).astype(np.float32)
-        ndx.shape = dx.shape
-        ndy.shape=dy.shape
-        return ndx, ndy
-
-    transformData = classmethod(transformData)
-
-    def getIDCCoeffs(cls, header):
-        """
-        Return a matrix of the scaled first order IDC coefficients.
-        """
-        try:
-            ocx10 = header['OCX10']
-            ocx11 = header['OCX11']
-            ocy10 = header['OCY10']
-            ocy11 = header['OCY11']
-            coeffs = np.array([[ocx11, ocx10], [ocy11,ocy10]], dtype=np.float32)
-        except KeyError:
-            logger.exception('\n\tFirst order IDCTAB coefficients are not available. \n\
-            Cannot convert SIP to IDC coefficients.')
-            return None
-        try:
-            idcscale = header['IDCSCALE']
-        except KeyError:
-            logger.exception("IDCSCALE not found in header - setting it to 1.")
-            idcscale = 1
-
-        return np.linalg.inv(coeffs/idcscale)
-
-    getIDCCoeffs = classmethod(getIDCCoeffs)
-
-    def createNpolHDU(cls, sciheader, npolfile=None, wdvarr_ver=1, npl_extname=None,data = None, ccdchip=1):
-        """
-        Creates an HDU to be added to the file object.
-        """
-        hdr = cls.createNpolHdr(sciheader, npolfile=npolfile, wdvarr_ver=wdvarr_ver, npl_extname=npl_extname, ccdchip=ccdchip)
-        hdu = fits.ImageHDU(header=hdr, data=data)
-        return hdu
-
-    createNpolHDU = classmethod(createNpolHDU)
-
-    def createNpolHdr(cls, sciheader, npolfile, wdvarr_ver, npl_extname, ccdchip):
-        """
-        Creates a header for the WCSDVARR extension based on the NPOL reference file
-        and sci extension header. The goal is to always work in image coordinates
-        (also for subarrays and binned images. The WCS for the WCSDVARR extension
-        i ssuch that a full size npol table is created and then shifted or scaled
-        if the science image is a subarray or binned image.
-        """
-        npl = fits.open(npolfile)
-        npol_phdr = npl[0].header
-        for ext in npl:
-            try:
-                nplextname = ext.header['EXTNAME']
-                nplextver = ext.header['EXTVER']
-            except KeyError:
-                continue
-            nplccdchip = cls.get_ccdchip(npl, extname=nplextname, extver=nplextver)
-            if nplextname == npl_extname and nplccdchip == ccdchip:
-                npol_header = ext.header
-                break
-            else:
-                continue
-        npl.close()
-
-        naxis = npl[1].header['NAXIS']
-        ccdchip = nplextname #npol_header['CCDCHIP']
-
-        kw = { 'NAXIS': 'Size of the axis',
-               'CDELT': 'Coordinate increment along axis',
-               'CRPIX': 'Coordinate system reference pixel',
-               'CRVAL': 'Coordinate system value at reference pixel',
-               }
-
-        kw_comm1 = {}
-        kw_val1 = {}
-        for key in kw.keys():
-            for i in range(1, naxis+1):
-                si = str(i)
-                kw_comm1[key+si] = kw[key]
-
-        for i in range(1, naxis+1):
-            si = str(i)
-            kw_val1['NAXIS'+si] = npol_header.get('NAXIS'+si)
-            kw_val1['CDELT'+si] = npol_header.get('CDELT'+si, 1.0) * \
-                                  sciheader.get('LTM'+si+'_'+si, 1)
-            kw_val1['CRPIX'+si] = npol_header.get('CRPIX'+si, 0.0)
-            kw_val1['CRVAL'+si] = (npol_header.get('CRVAL'+si, 0.0) - \
-                                  sciheader.get('LTV'+str(i), 0))
-
-        kw_comm0 = {'XTENSION': 'Image extension',
-                    'BITPIX': 'IEEE floating point',
-                    'NAXIS': 'Number of axes',
-                    'EXTNAME': 'WCS distortion array',
-                    'EXTVER': 'Distortion array version number',
-                    'PCOUNT': 'Special data area of size 0',
-                    'GCOUNT': 'One data group',
-                    }
-
-        kw_val0 = { 'XTENSION': 'IMAGE',
-                    'BITPIX': -32,
-                    'NAXIS': naxis,
-                    'EXTNAME': 'WCSDVARR',
-                    'EXTVER':  wdvarr_ver,
-                    'PCOUNT': 0,
-                    'GCOUNT': 1,
-                    'CCDCHIP': ccdchip,
-                }
-        cdl = []
-        for key in kw_comm0.keys():
-            cdl.append((key, kw_val0[key], kw_comm0[key]))
-        for key in kw_comm1.keys():
-            cdl.append((key, kw_val1[key], kw_comm1[key]))
-        # Now add keywords from NPOLFILE header to document source of calibration
-        # include all keywords after and including 'FILENAME' from header
-        start_indx = -1
-        end_indx = 0
-        for i, c in enumerate(npol_phdr):
-            if c == 'FILENAME':
-                start_indx = i
-            if c == '': # remove blanks from end of header
-                end_indx = i+1
-                break
-        if start_indx >= 0:
-            for card in npol_phdr.cards[start_indx:end_indx]:
-                cdl.append(card)
-
-        hdr = fits.Header(cards=cdl)
-
-        return hdr
-
-    createNpolHdr = classmethod(createNpolHdr)
-
-    def get_ccdchip(cls, fobj, extname, extver):
-        """
-        Given a science file or npol file determine CCDCHIP
-        """
-        ccdchip = 1
-        if fobj[0].header['INSTRUME'] == 'ACS' and fobj[0].header['DETECTOR'] == 'WFC':
-            ccdchip = fobj[extname, extver].header['CCDCHIP']
-        elif fobj[0].header['INSTRUME'] == 'WFC3' and fobj[0].header['DETECTOR'] == 'UVIS':
-            ccdchip =  fobj[extname, extver].header['CCDCHIP']
-        elif fobj[0].header['INSTRUME'] == 'WFPC2':
-            ccdchip = fobj[extname, extver].header['DETECTOR']
-        elif fobj[0].header['INSTRUME'] == 'STIS':
-            ccdchip = fobj[extname, extver].header['DETECTOR']
-        elif fobj[0].header['INSTRUME'] == 'NICMOS':
-            ccdchip = fobj[extname, extver].header['CAMERA']
-        return ccdchip
-
-    get_ccdchip = classmethod(get_ccdchip)
diff --git a/lib/stwcs/updatewcs/utils.py b/lib/stwcs/updatewcs/utils.py
deleted file mode 100644
index 1214199..0000000
--- a/lib/stwcs/updatewcs/utils.py
+++ /dev/null
@@ -1,264 +0,0 @@
-from __future__ import division # confidence high
-import os
-from astropy.io import fits
-from stsci.tools import fileutil
-
-import logging
-logger = logging.getLogger("stwcs.updatewcs.utils")
-
-
-def diff_angles(a,b):
-    """
-    Perform angle subtraction a-b taking into account
-    small-angle differences across 360degree line.
-    """
-
-    diff = a - b
-
-    if diff > 180.0:
-        diff -= 360.0
-
-    if diff < -180.0:
-        diff += 360.0
-
-    return diff
-
-def getBinning(fobj, extver=1):
-    # Return the binning factor
-    binned = 1
-    if fobj[0].header['INSTRUME'] == 'WFPC2':
-        mode = fobj[0].header.get('MODE', "")
-        if mode == 'AREA': binned = 2
-    else:
-        binned = fobj['SCI', extver].header.get('BINAXIS',1)
-    return binned
-
-def updateNEXTENDKw(fobj):
-    """
-    Updates PRIMARY header with correct value for NEXTEND, if present.
-
-    Parameters
-    -----------
-    fobj : `astropy.io.fits.HDUList`
-        The FITS object for file opened in `update` mode
-
-    """
-    if 'nextend' in fobj[0].header:
-        fobj[0].header['nextend'] = len(fobj) -1
-
-def extract_rootname(kwvalue,suffix=""):
-    """ Returns the rootname from a full reference filename
-
-        If a non-valid value (any of ['','N/A','NONE','INDEF',None]) is input,
-            simply return a string value of 'NONE'
-
-        This function will also replace any 'suffix' specified with a blank.
-    """
-    # check to see whether a valid kwvalue has been provided as input
-    if kwvalue.strip() in ['','N/A','NONE','INDEF',None]:
-        return 'NONE' # no valid value, so return 'NONE'
-
-    # for a valid kwvalue, parse out the rootname
-    # strip off any environment variable from input filename, if any are given
-    if '$' in kwvalue:
-        fullval = kwvalue[kwvalue.find('$')+1:]
-    else:
-        fullval = kwvalue
-    # Extract filename without path from kwvalue
-    fname = os.path.basename(fullval).strip()
-
-    # Now, rip out just the rootname from the full filename
-    rootname = fileutil.buildNewRootname(fname)
-
-    # Now, remove any known suffix from rootname
-    rootname = rootname.replace(suffix,'')
-    return rootname.strip()
-
-def construct_distname(fobj,wcsobj):
-    """
-    This function constructs the value for the keyword 'DISTNAME'.
-    It relies on the reference files specified by the keywords 'IDCTAB',
-    'NPOLFILE', and 'D2IMFILE'.
-
-    The final constructed value will be of the form:
-        <idctab rootname>-<npolfile rootname>-<d2imfile rootname>
-    and have a value of 'NONE' if no reference files are specified.
-    """
-    idcname = extract_rootname(fobj[0].header.get('IDCTAB', "NONE"),
-                                suffix='_idc')
-    if (idcname is None or idcname=='NONE') and wcsobj.sip is not None:
-        idcname = 'UNKNOWN'
-
-    npolname, npolfile = build_npolname(fobj)
-    if npolname is None and wcsobj.cpdis1 is not None:
-        npolname = 'UNKNOWN'
-
-    d2imname, d2imfile = build_d2imname(fobj)
-    if d2imname is None and wcsobj.det2im is not None:
-        d2imname = 'UNKNOWN'
-
-    sipname, idctab = build_sipname(fobj)
-
-    distname = build_distname(sipname,npolname,d2imname)
-    return {'DISTNAME':distname,'SIPNAME':sipname}
-
-def build_distname(sipname,npolname,d2imname):
-    """
-    Core function to build DISTNAME keyword value without the HSTWCS input.
-    """
-
-    distname = sipname.strip()
-    if npolname != 'NONE' or d2imname != 'NONE':
-        if d2imname != 'NONE':
-            distname+= '-'+npolname.strip() + '-'+d2imname.strip()
-        else:
-            distname+='-'+npolname.strip()
-
-    return distname
-
-def build_default_wcsname(idctab):
-
-    idcname = extract_rootname(idctab,suffix='_idc')
-    wcsname = 'IDC_' + idcname
-    return wcsname
-
-def build_sipname(fobj, fname=None, sipname=None):
-    """
-    Build a SIPNAME from IDCTAB
-
-    Parameters
-    ----------
-    fobj : `astropy.io.fits.HDUList`
-        file object
-    fname : string
-          science file name (to be used if ROOTNAME is not present
-    sipname : string
-          user supplied SIPNAME keyword
-
-    Returns
-    -------
-    sipname, idctab
-    """
-    try:
-        idctab = fobj[0].header['IDCTAB']
-        idcname = extract_rootname(idctab,suffix='_idc')
-    except KeyError:
-        idctab = 'N/A'
-        idcname= 'N/A'
-    if not fname:
-        try:
-            fname = fobj.filename()
-        except:
-            fname = " "
-    if not sipname:
-        try:
-            sipname = fobj[0].header["SIPNAME"]
-            if idcname == 'N/A' or idcname not in sipname:
-                raise KeyError
-        except KeyError:
-            if idcname != 'N/A':
-                try:
-                    rootname = fobj[0].header['rootname']
-                except KeyError:
-                    rootname = fname
-                sipname = rootname +'_'+ idcname
-            else:
-                if 'A_ORDER' in fobj[1].header or 'B_ORDER' in fobj[1].header:
-                    sipname = 'UNKNOWN'
-                else:
-                    idcname = 'NOMODEL'
-
-    return sipname, idctab
-
-def build_npolname(fobj, npolfile=None):
-    """
-    Build a NPOLNAME from NPOLFILE
-
-    Parameters
-    ----------
-    fobj : `astropy.io.fits.HDUList`
-        file object
-    npolfile : string
-        user supplied NPOLFILE keyword
-
-    Returns
-    -------
-    npolname, npolfile
-    """
-    if not npolfile:
-        try:
-            npolfile = fobj[0].header["NPOLFILE"]
-        except KeyError:
-            npolfile = ' '
-            if fileutil.countExtn(fobj, 'WCSDVARR'):
-                npolname = 'UNKNOWN'
-            else:
-                npolname = 'NOMODEL'
-        npolname = extract_rootname(npolfile, suffix='_npl')
-        if npolname == 'NONE':
-            npolname = 'NOMODEL'
-    else:
-        npolname = extract_rootname(npolfile, suffix='_npl')
-        if npolname == 'NONE':
-            npolname = 'NOMODEL'
-    return npolname, npolfile
-
-def build_d2imname(fobj, d2imfile=None):
-    """
-    Build a D2IMNAME from D2IMFILE
-
-    Parameters
-    ----------
-    fobj : `astropy.io.fits.HDUList`
-        file object
-    d2imfile : string
-        user supplied NPOLFILE keyword
-
-    Returns
-    -------
-    d2imname, d2imfile
-    """
-    if not d2imfile:
-        try:
-            d2imfile = fobj[0].header["D2IMFILE"]
-        except KeyError:
-            d2imfile = 'N/A'
-            if fileutil.countExtn(fobj, 'D2IMARR'):
-                d2imname = 'UNKNOWN'
-            else:
-                d2imname = 'NOMODEL'
-        d2imname = extract_rootname(d2imfile,suffix='_d2i')
-        if d2imname == 'NONE':
-            d2imname = 'NOMODEL'
-    else:
-        d2imname = extract_rootname(d2imfile,suffix='_d2i')
-        if d2imname == 'NONE':
-            d2imname = 'NOMODEL'
-    return d2imname, d2imfile
-
-
-def remove_distortion(fname, dist_keyword):
-    logger.info("Removing distortion {0} from file {0}".format(dist_keyword, fname))
-    from ..wcsutil import altwcs
-    if dist_keyword == "NPOLFILE":
-        extname = "WCSDVARR"
-        keywords = ["CPERR*", "DP1.*", "DP2.*", "CPDIS*", "NPOLEXT"]
-    elif dist_keyword == "D2IMFILE":
-        extname = "D2IMARR"
-        keywords = ["D2IMERR*", "D2IM1.*", "D2IM2.*", "D2IMDIS*", "D2IMEXT"]
-    else:
-        raise AttributeError("Unrecognized distortion keyword "
-                             "{0} when attempting to remove distortion".format(dist_keyword))
-    ext_mapping = altwcs.mapFitsExt2HDUListInd(fname, "SCI").values()
-    f = fits.open(fname, mode="update")
-    for hdu in ext_mapping:
-        for kw in keywords:
-            try:
-                del f[hdu].header[kw]
-            except KeyError:
-                pass
-    ext_mapping = altwcs.mapFitsExt2HDUListInd(fname, extname).values()
-    ext_mapping.sort()
-    for hdu in ext_mapping[::-1]:
-        del f[hdu]
-    f.close()
diff --git a/lib/stwcs/updatewcs/wfpc2_dgeo.py b/lib/stwcs/updatewcs/wfpc2_dgeo.py
deleted file mode 100644
index e57bb5c..0000000
--- a/lib/stwcs/updatewcs/wfpc2_dgeo.py
+++ /dev/null
@@ -1,123 +0,0 @@
-""" wfpc2_dgeo - Functions to convert WFPC2 DGEOFILE into D2IMFILE
-
-"""
-import os
-import datetime
-
-import astropy
-from astropy.io import fits
-import numpy as np
-
-from stsci.tools import fileutil
-
-import logging
-logger = logging.getLogger("stwcs.updatewcs.apply_corrections")
-
-def update_wfpc2_d2geofile(filename, fhdu=None):
-    """
-    Creates a D2IMFILE from the DGEOFILE for a WFPC2 image (input), and
-    modifies the header to reflect the new usage.
-
-    Parameters
-    ----------
-    filename: string
-        Name of WFPC2 file to be processed.  This file will be updated
-        to delete any reference to a DGEOFILE and add a D2IMFILE to replace
-        that correction when running updatewcs.
-    fhdu: object
-        FITS object for WFPC2 image.  If user has already opened the WFPC2
-        file, they can simply pass that FITS object in for direct processing.
-
-    Returns
-    -------
-    d2imfile: string
-        Name of D2IMFILE created from DGEOFILE.  The D2IMFILE keyword in the
-        image header will be updated/added to point to this newly created file.
-
-    """
-    
-    close_fhdu = False
-    if fhdu is None:
-        fhdu = fileutil.openImage(filename, mode='update')
-        close_fhdu = True
-
-    dgeofile = fhdu['PRIMARY'].header.get('DGEOFILE', None)
-    already_converted = dgeofile not in [None, "N/A", "", " "]
-    if already_converted or 'ODGEOFIL' in fhdu['PRIMARY'].header:
-        if not already_converted:
-            dgeofile = fhdu['PRIMARY'].header.get('ODGEOFIL', None)
-        logger.info('Converting DGEOFILE %s into D2IMFILE...' % dgeofile)
-        rootname = filename[:filename.find('.fits')]
-        d2imfile = convert_dgeo_to_d2im(dgeofile,rootname)
-        fhdu['PRIMARY'].header['ODGEOFIL'] = dgeofile
-        fhdu['PRIMARY'].header['DGEOFILE'] = 'N/A'
-        fhdu['PRIMARY'].header['D2IMFILE'] = d2imfile
-    else:
-        d2imfile = None
-        fhdu['PRIMARY'].header['DGEOFILE'] = 'N/A'
-        if 'D2IMFILE' not in fhdu['PRIMARY'].header:
-            fhdu['PRIMARY'].header['D2IMFILE'] = 'N/A'
-
-    # Only close the file handle if opened in this function
-    if close_fhdu:
-        fhdu.close()
-
-    # return the d2imfile name so that calling routine can keep
-    # track of the new file created and delete it later if necessary
-    # (multidrizzle clean=True mode of operation)
-    return d2imfile
-
-def convert_dgeo_to_d2im(dgeofile,output,clobber=True):
-    """ Routine that converts the WFPC2 DGEOFILE into a D2IMFILE.
-    """
-    dgeo = fileutil.openImage(dgeofile)
-    outname = output+'_d2im.fits'
-
-    removeFileSafely(outname)
-    data = np.array([dgeo['dy',1].data[:,0]])
-    scihdu = fits.ImageHDU(data=data)
-    dgeo.close()
-    # add required keywords for D2IM header
-    scihdu.header['EXTNAME'] = ('DY', 'Extension name')
-    scihdu.header['EXTVER'] = (1, 'Extension version')
-    fits_str = 'PYFITS Version '+str(astropy.__version__)
-    scihdu.header['ORIGIN'] = (fits_str, 'FITS file originator')
-    scihdu.header['INHERIT'] = (False, 'Inherits global header')
-
-    dnow = datetime.datetime.now()
-    scihdu.header['DATE'] = (str(dnow).replace(' ','T'),
-                             'Date FITS file was generated')
-
-    scihdu.header['CRPIX1'] = (0, 'Distortion array reference pixel')
-    scihdu.header['CDELT1'] = (1, 'Grid step size in first coordinate')
-    scihdu.header['CRVAL1'] = (0, 'Image array pixel coordinate')
-    scihdu.header['CRPIX2'] = (0, 'Distortion array reference pixel')
-    scihdu.header['CDELT2'] = (1, 'Grid step size in second coordinate')
-    scihdu.header['CRVAL2'] = (0, 'Image array pixel coordinate')
-
-    phdu = fits.PrimaryHDU()
-    phdu.header['INSTRUME'] = 'WFPC2'
-    d2imhdu = fits.HDUList()
-    d2imhdu.append(phdu)
-    scihdu.header['DETECTOR'] = (1, 'CCD number of the detector: PC 1, WFC 2-4 ')
-    d2imhdu.append(scihdu.copy())
-    scihdu.header['EXTVER'] = (2, 'Extension version')
-    scihdu.header['DETECTOR'] = (2, 'CCD number of the detector: PC 1, WFC 2-4 ')
-    d2imhdu.append(scihdu.copy())
-    scihdu.header['EXTVER'] = (3, 'Extension version')
-    scihdu.header['DETECTOR'] = (3, 'CCD number of the detector: PC 1, WFC 2-4 ')
-    d2imhdu.append(scihdu.copy())
-    scihdu.header['EXTVER'] = (4, 'Extension version')
-    scihdu.header['DETECTOR'] = (4, 'CCD number of the detector: PC 1, WFC 2-4 ')
-    d2imhdu.append(scihdu.copy())
-    d2imhdu.writeto(outname)
-    d2imhdu.close()
-
-    return outname
-
-
-def removeFileSafely(filename,clobber=True):
-    """ Delete the file specified, but only if it exists and clobber is True.
-    """
-    if filename is not None and filename.strip() != '':
-        if os.path.exists(filename) and clobber: os.remove(filename)
diff --git a/lib/stwcs/wcsutil/__init__.py b/lib/stwcs/wcsutil/__init__.py
deleted file mode 100644
index 65280be..0000000
--- a/lib/stwcs/wcsutil/__init__.py
+++ /dev/null
@@ -1,34 +0,0 @@
-from __future__ import absolute_import, print_function # confidence high
-
-from .altwcs import *
-from .hstwcs import HSTWCS
-
-
-def help():
-    doc = """ \
-    1. Using a `astropy.io.fits.HDUList` object and an extension number \n
-    Example:\n
-    from astropy.io improt fits
-    fobj = fits.open('some_file.fits')\n
-    w = wcsutil.HSTWCS(fobj, 3)\n\n
-
-    2. Create an HSTWCS object using a qualified file name. \n
-    Example:\n
-    w = wcsutil.HSTWCS('j9irw4b1q_flt.fits[sci,1]')\n\n
-
-    3. Create an HSTWCS object using a file name and an extension number. \n
-    Example:\n
-    w = wcsutil.HSTWCS('j9irw4b1q_flt.fits', ext=2)\n\n
-
-    4. Create an HSTWCS object from WCS with key 'O'.\n
-    Example:\n
-
-    w = wcsutil.HSTWCS('j9irw4b1q_flt.fits', ext=2, wcskey='O')\n\n
-
-    5. Create a template HSTWCS object for a DEFAULT object.\n
-    Example:\n
-    w = wcsutil.HSTWCS(instrument='DEFAULT')\n\n
-    """
-
-    print('How to create an HSTWCS object:\n\n')
-    print(doc)
diff --git a/lib/stwcs/wcsutil/altwcs.py b/lib/stwcs/wcsutil/altwcs.py
deleted file mode 100644
index aae1a9f..0000000
--- a/lib/stwcs/wcsutil/altwcs.py
+++ /dev/null
@@ -1,758 +0,0 @@
-from __future__ import division, print_function # confidence high
-import os
-import string
-
-import numpy as np
-from astropy import wcs as pywcs
-from astropy.io import fits
-from stsci.tools import fileutil as fu
-
-altwcskw = ['WCSAXES', 'CRVAL', 'CRPIX', 'PC', 'CDELT', 'CD', 'CTYPE', 'CUNIT',
-            'PV', 'PS']
-altwcskw_extra = ['LATPOLE','LONPOLE','RESTWAV','RESTFRQ']
-
-# file operations
-def archiveWCS(fname, ext, wcskey=" ", wcsname=" ", reusekey=False):
-    """
-    Copy the primary WCS to the header as an alternate WCS
-    with wcskey and name WCSNAME. It loops over all extensions in 'ext'
-
-    Parameters
-    ----------
-    fname :  string or `astropy.io.fits.HDUList`
-        file name or a file object
-    ext :    int, tuple, str, or list of integers or tuples (e.g.('sci',1))
-        fits extensions to work with
-        If a string is provided, it should specify the EXTNAME of extensions
-        with WCSs to be archived
-    wcskey : string "A"-"Z" or " "
-        if " ": get next available key if wcsname is also " " or try
-        to get a key from WCSNAME value
-    wcsname : string
-        Name of alternate WCS description
-    reusekey : boolean
-        if True - overwrites a WCS with the same key
-
-    Examples
-    --------
-    Copy the primary WCS of an in memory headrlet object to an
-    alternate WCS with key 'T'
-
-    >>> hlet=headerlet.createHeaderlet('junk.fits', 'hdr1.fits')
-    >>> altwcs.wcskeys(hlet[1].header)
-    ['A']
-    >>> altwcs.archiveWCS(hlet, ext=[('SIPWCS',1),('SIPWCS',2)], wcskey='T')
-    >>> altwcs.wcskeys(hlet[1].header)
-    ['A', 'T']
-
-
-    See Also
-    --------
-    wcsutil.restoreWCS: Copy an alternate WCS to the primary WCS
-
-    """
-
-    if isinstance(fname, str):
-        f = fits.open(fname, mode='update')
-    else:
-        f = fname
-
-    if not _parpasscheck(f, ext, wcskey, wcsname):
-        closefobj(fname, f)
-        raise ValueError("Input parameters problem")
-
-    # Interpret input 'ext' value to get list of extensions to process
-    ext = _buildExtlist(f, ext)
-
-    if not wcskey and not wcsname:
-        raise KeyError("Either wcskey or wcsname should be specified")
-
-    if wcsname.strip() == "":
-        try:
-            wcsname = readAltWCS(f, ext[0], wcskey=" ")['WCSNAME']
-        except KeyError:
-            pass
-    wcsext = ext[0]
-    if wcskey != " " and wcskey in wcskeys(f[wcsext].header) and not reusekey:
-        closefobj(fname, f)
-        raise KeyError("Wcskey %s is aready used. \
-        Run archiveWCS() with reusekey=True to overwrite this alternate WCS. \
-        Alternatively choose another wcskey with altwcs.available_wcskeys()." %wcskey)
-    elif wcskey == " ":
-        # wcsname exists, overwrite it if reuse is True or get the next key
-        if wcsname.strip() in wcsnames(f[wcsext].header).values():
-            if reusekey:
-                # try getting the key from an existing WCS with WCSNAME
-                wkey = getKeyFromName(f[wcsext].header, wcsname)
-                wname = wcsname
-                if wkey == ' ':
-                    wkey = next_wcskey(f[wcsext].header)
-                elif wkey is None:
-                    closefobj(fname, f)
-                    raise KeyError("Could not get a valid wcskey from wcsname %s" %wcsname)
-            else:
-                closefobj(fname, f)
-                raise KeyError("Wcsname %s is aready used. \
-                Run archiveWCS() with reusekey=True to overwrite this alternate WCS. \
-                Alternatively choose another wcskey with altwcs.available_wcskeys() or\
-                choose another wcsname." %wcsname)
-        else:
-            wkey = next_wcskey(f[wcsext].header)
-            if wcsname.strip():
-                wname = wcsname
-            else:
-                # determine which WCSNAME needs to be replicated in archived WCS
-                wnames = wcsnames(f[wcsext].header)
-                if 'O' in wnames: del wnames['O'] # we don't want OPUS/original
-                if len(wnames) > 0:
-                    if ' ' in wnames:
-                        wname = wnames[' ']
-                    else:
-                        akeys = string.uppercase
-                        wname = "DEFAULT"
-                        for key in akeys[-1::]:
-                            if key in wnames:
-                                wname = wnames
-                                break
-                else:
-                    wname = "DEFAULT"
-    else:
-        wkey = wcskey
-        wname = wcsname
-
-    for e in ext:
-        hwcs = readAltWCS(f,e,wcskey=' ')
-        if hwcs is None:
-            continue
-
-        wcsnamekey = 'WCSNAME' + wkey
-        f[e].header[wcsnamekey] = wname
-
-        try:
-            old_wcsname=hwcs.pop('WCSNAME')
-        except:
-            pass
-        
-        for k in hwcs.keys():
-            key = k[:7] + wkey
-            f[e].header[key] = hwcs[k]
-    closefobj(fname, f)
-
-def restore_from_to(f, fromext=None, toext=None, wcskey=" ", wcsname=" "):
-    """
-    Copy an alternate WCS from one extension as a primary WCS of another extension
-
-    Reads in a WCS defined with wcskey and saves it as the primary WCS.
-    Goes sequentially through the list of extensions in ext.
-    Alternatively uses 'fromext' and 'toext'.
-
-
-    Parameters
-    ----------
-    f:       string or `astropy.io.fits.HDUList`
-             a file name or a file object
-    fromext: string
-             extname from which to read in the alternate WCS, for example 'SCI'
-    toext:   string or python list
-             extname or a list of extnames to which the WCS will be copied as
-             primary, for example ['SCI', 'ERR', 'DQ']
-    wcskey:  a charater
-             "A"-"Z" - Used for one of 26 alternate WCS definitions.
-             or " " - find a key from WCSNAMe value
-    wcsname: string (optional)
-             if given and wcskey is " ", will try to restore by WCSNAME value
-
-    See Also
-    --------
-    archiveWCS - copy the primary WCS as an alternate WCS
-    restoreWCS - Copy a WCS with key "WCSKEY" to the primary WCS
-
-    """
-    if isinstance(f, str):
-        fobj = fits.open(f, mode='update')
-    else:
-        fobj = f
-
-    if not _parpasscheck(fobj, ext=None, wcskey=wcskey, fromext=fromext, toext=toext):
-        closefobj(f, fobj)
-        raise ValueError("Input parameters problem")
-
-    # Interpret input 'ext' value to get list of extensions to process
-    #ext = _buildExtlist(fobj, ext)
-
-    if isinstance(toext, str):
-        toext = [toext]
-
-    # the case of an HDUList object in memory without an associated file
-
-    #if fobj.filename() is not None:
-    #        name = fobj.filename()
-
-    simplefits = fu.isFits(fobj)[1] is 'simple'
-    if simplefits:
-        wcskeyext = 0
-    else:
-        wcskeyext = 1
-
-    if wcskey == " ":
-        if wcsname.strip():
-            wkey = getKeyFromName(fobj[wcskeyext].header, wcsname)
-            if not wkey:
-                closefobj(f, fobj)
-                raise KeyError("Could not get a key from wcsname %s ." % wcsname)
-    else:
-        if wcskey not in wcskeys(fobj, ext=wcskeyext):
-            print("Could not find alternate WCS with key %s in this file" % wcskey)
-            closefobj(f, fobj)
-            return
-        wkey = wcskey
-
-    countext = fu.countExtn(fobj, fromext)
-    if not countext:
-        raise KeyError("File does not have extension with extname %s", fromext)
-    else:
-        for i in range(1, countext+1):
-            for toe in toext:
-                _restore(fobj, fromextnum=i, fromextnam=fromext, toextnum=i, toextnam=toe, ukey=wkey)
-
-    if fobj.filename() is not None:
-        #fobj.writeto(name)
-        closefobj(f, fobj)
-
-def restoreWCS(f, ext, wcskey=" ", wcsname=" "):
-    """
-    Copy a WCS with key "WCSKEY" to the primary WCS
-
-    Reads in a WCS defined with wcskey and saves it as the primary WCS.
-    Goes sequentially through the list of extensions in ext.
-    Alternatively uses 'fromext' and 'toext'.
-
-
-    Parameters
-    ----------
-    f : str or `astropy.io.fits.HDUList`
-        file name or a file object
-    ext : int, tuple, str, or list of integers or tuples (e.g.('sci',1))
-        fits extensions to work with
-        If a string is provided, it should specify the EXTNAME of extensions
-        with WCSs to be archived
-    wcskey : str
-        "A"-"Z" - Used for one of 26 alternate WCS definitions.
-        or " " - find a key from WCSNAMe value
-    wcsname : str
-        (optional) if given and wcskey is " ", will try to restore by WCSNAME value
-
-    See Also
-    --------
-    archiveWCS - copy the primary WCS as an alternate WCS
-    restore_from_to
-
-    """
-    if isinstance(f, str):
-        fobj = fits.open(f, mode='update')
-    else:
-        fobj = f
-
-    if not _parpasscheck(fobj, ext=ext, wcskey=wcskey):
-        closefobj(f, fobj)
-        raise ValueError("Input parameters problem")
-
-    # Interpret input 'ext' value to get list of extensions to process
-    ext = _buildExtlist(fobj, ext)
-
-
-    # the case of an HDUList object in memory without an associated file
-
-    #if fobj.filename() is not None:
-    #        name = fobj.filename()
-
-    simplefits = fu.isFits(fobj)[1] is 'simple'
-    if simplefits:
-        wcskeyext = 0
-    else:
-        wcskeyext = 1
-
-    if wcskey == " ":
-        if wcsname.strip():
-            wkey = getKeyFromName(fobj[wcskeyext].header, wcsname)
-            if not wkey:
-                closefobj(f, fobj)
-                raise KeyError("Could not get a key from wcsname %s ." % wcsname)
-    else:
-        if wcskey not in wcskeys(fobj, ext=wcskeyext):
-            #print "Could not find alternate WCS with key %s in this file" % wcskey
-            closefobj(f, fobj)
-            return
-        wkey = wcskey
-
-    for e in ext:
-        _restore(fobj, wkey, fromextnum=e, verbose=False)
-
-    if fobj.filename() is not None:
-        #fobj.writeto(name)
-        closefobj(f, fobj)
-
-def deleteWCS(fname, ext, wcskey=" ", wcsname=" "):
-    """
-    Delete an alternate WCS defined with wcskey.
-    If wcskey is " " try to get a key from WCSNAME.
-
-    Parameters
-    ----------
-    fname : str or a `astropy.io.fits.HDUList`
-    ext : int, tuple, str, or list of integers or tuples (e.g.('sci',1))
-        fits extensions to work with
-        If a string is provided, it should specify the EXTNAME of extensions
-        with WCSs to be archived
-    wcskey : str
-        one of 'A'-'Z' or " "
-    wcsname : str
-        Name of alternate WCS description
-    """
-    if isinstance(fname, str):
-        fobj = fits.open(fname, mode='update')
-    else:
-        fobj = fname
-
-    if not _parpasscheck(fobj, ext, wcskey, wcsname):
-        closefobj(fname, fobj)
-        raise ValueError("Input parameters problem")
-
-    # Interpret input 'ext' value to get list of extensions to process
-    ext = _buildExtlist(fobj, ext)
-    # Do not allow deleting the original WCS.
-    if wcskey == 'O':
-        print("Wcskey 'O' is reserved for the original WCS and should not be deleted.")
-        closefobj(fname, fobj)
-        return
-
-    wcskeyext = ext[0]
-
-    if not wcskeys and not wcsname:
-        raise KeyError("Either wcskey or wcsname should be specified")
-
-    if wcskey == " ":
-        # try getting the key from WCSNAME
-        wkey = getKeyFromName(fobj[wcskeyext].header, wcsname)
-        if not wkey:
-            closefobj(fname, fobj)
-            raise KeyError("Could not get a key: wcsname '%s' not found in header." % wcsname)
-    else:
-        if wcskey not in wcskeys(fobj[wcskeyext].header):
-            closefobj(fname, fobj)
-            raise KeyError("Could not find alternate WCS with key %s in this file" % wcskey)
-        wkey = wcskey
-
-    prexts = []
-    for i in ext:
-        hdr = fobj[i].header
-        hwcs = readAltWCS(fobj,i,wcskey=wkey)
-        if hwcs is None:
-            continue
-        for k in hwcs[::-1]:
-            del hdr[k]
-            #del hdr['ORIENT'+wkey]
-        prexts.append(i)
-    if prexts != []:
-        print('Deleted all instances of WCS with key %s in extensions' % wkey, prexts)
-    else:
-        print("Did not find WCS with key %s in any of the extensions" % wkey)
-    closefobj(fname, fobj)
-
-def _buildExtlist(fobj, ext):
-    """
-    Utility function to interpret the provided value of 'ext' and return a list
-    of 'valid' values which can then be used by the rest of the functions in
-    this module.
-
-    Parameters
-    ----------
-    fobj: HDUList
-        file to be examined
-    ext:    an int, a tuple, string, list of integers or tuples (e.g.('sci',1))
-            fits extensions to work with
-            If a string is provided, it should specify the EXTNAME of extensions
-            with WCSs to be archived
-    """
-    if not isinstance(ext,list):
-        if isinstance(ext,str):
-            extstr = ext
-            ext = []
-            for extn in range(1, len(fobj)):
-                if 'extname' in fobj[extn].header and fobj[extn].header['extname'] == extstr:
-                    ext.append(extn)
-        elif isinstance(ext, int) or isinstance(ext, tuple):
-            ext = [ext]
-        else:
-            raise KeyError("Valid extensions in 'ext' parameter need to be specified.")
-    return ext
-
-def _restore(fobj, ukey, fromextnum,
-             toextnum=None, fromextnam=None, toextnam=None, verbose=True):
-    """
-    fobj: string of HDUList
-    ukey: string 'A'-'Z'
-          wcs key
-    fromextnum: int
-                extver of extension from which to copy WCS
-    fromextnam: string
-                extname of extension from which to copy WCS
-    toextnum: int
-              extver of extension to which to copy WCS
-    toextnam: string
-              extname of extension to which to copy WCS
-    """
-    # create an extension tuple, e.g. ('SCI', 2)
-    if fromextnam:
-        fromextension = (fromextnam, fromextnum)
-    else:
-        fromextension = fromextnum
-    if toextnum:
-        if toextnam:
-            toextension = (toextnam, toextnum)
-        else:
-            toextension =toextnum
-    else:
-        toextension = fromextension
-
-    hwcs = readAltWCS(fobj,fromextension,wcskey=ukey,verbose=verbose)
-    if hwcs is None:
-        return
-
-    for k in hwcs.keys():
-        key = k[:-1]
-        if key in fobj[toextension].header:
-            #fobj[toextension].header.update(key=key, value = hwcs[k])
-            fobj[toextension].header[key] = hwcs[k]
-        else:
-            continue
-    if key == 'O' and 'TDDALPHA' in fobj[toextension].header:
-        fobj[toextension].header['TDDALPHA'] = 0.0
-        fobj[toextension].header['TDDBETA'] = 0.0
-    if 'ORIENTAT' in fobj[toextension].header:
-        norient = np.rad2deg(np.arctan2(hwcs['CD1_2'+'%s' %ukey], hwcs['CD2_2'+'%s' %ukey]))
-        fobj[toextension].header['ORIENTAT'] = norient
-    # Reset 2014 TDD keywords prior to computing new values (if any are computed)
-    for kw in ['TDD_CYA','TDD_CYB','TDD_CXA','TDD_CXB']:
-        if kw in fobj[toextension].header:
-            fobj[toextension].header[kw] = 0.0
-
-#header operations
-def _check_headerpars(fobj, ext):
-    if not isinstance(fobj, fits.Header) and not isinstance(fobj, fits.HDUList) \
-                   and not isinstance(fobj, str):
-        raise ValueError("Expected a file name, a file object or a header\n")
-
-    if not isinstance(fobj, fits.Header):
-        #raise ValueError("Expected a valid ext parameter when input is a file")
-        if not isinstance(ext, int) and not isinstance(ext, tuple):
-            raise ValueError("Expected ext to be a number or a tuple, e.g. ('SCI', 1)\n")
-
-def _getheader(fobj, ext):
-    if isinstance(fobj, str):
-        hdr = fits.getheader(fobj,ext)
-    elif isinstance(fobj, fits.Header):
-        hdr = fobj
-    else:
-        hdr = fobj[ext].header
-    return hdr
-
-def readAltWCS(fobj, ext, wcskey=' ',verbose=False):
-    """ Reads in alternate WCS from specified extension
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList`
-        fits filename or fits file object
-        containing alternate/primary WCS(s) to be converted
-    wcskey : str
-        [" ",A-Z]
-        alternate/primary WCS key that will be replaced by the new key
-    ext : int
-        fits extension number
-
-    Returns
-    -------
-    hdr: fits.Header
-        header object with ONLY the keywords for specified alternate WCS
-    """
-    if isinstance(fobj, str):
-        fobj = fits.open(fobj)
-
-    hdr = _getheader(fobj,ext)
-    try:
-        nwcs = pywcs.WCS(hdr, fobj=fobj, key=wcskey)
-    except KeyError:
-        if verbose:
-            print('readAltWCS: Could not read WCS with key %s' %wcskey)
-            print('            Skipping %s[%s]' % (fobj.filename(), str(ext)))
-        return None
-    hwcs = nwcs.to_header()
-
-    if nwcs.wcs.has_cd():
-        hwcs = pc2cd(hwcs, key=wcskey)
-
-    return hwcs
-
-def convertAltWCS(fobj,ext,oldkey=" ",newkey=' '):
-    """
-    Translates the alternate/primary WCS with one key to an alternate/primary WCS with
-    another key.
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList`, or `astropy.io.fits.Header`
-        fits filename, fits file object or fits header
-        containing alternate/primary WCS(s) to be converted
-    ext : int
-        extension number
-    oldkey : str
-        [" ",A-Z]
-        alternate/primary WCS key that will be replaced by the new key
-    newkey : str
-        [" ",A-Z]
-        new alternate/primary WCS key
-
-    Returns
-    -------
-    hdr: `astropy.io.fits.Header`
-        header object with keywords renamed from oldkey to newkey
-    """
-    hdr = readAltWCS(fobj,ext,wcskey=oldkey)
-    if hdr is None:
-        return None
-    # Converting WCS to new key
-    for card in hdr:
-        if oldkey == ' ' or oldkey == '':
-            cname = card
-        else:
-            cname = card.rstrip(oldkey)
-        hdr.rename_key(card,cname+newkey,force=True)
-
-    return hdr
-
-def wcskeys(fobj, ext=None):
-    """
-    Returns a list of characters used in the header for alternate
-    WCS description with WCSNAME keyword
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList` or `astropy.io.fits.Header`
-          fits file name, fits file object or fits header
-    ext : int or None
-         extension number
-         if None, fobj must be a header
-    """
-    _check_headerpars(fobj, ext)
-    hdr = _getheader(fobj, ext)
-    names = hdr["WCSNAME*"]
-    d = []
-    for key in names:
-        wkey = key.replace('WCSNAME','')
-        if wkey == '': wkey = ' '
-        d.append(wkey)
-    return d
-
-def wcsnames(fobj, ext=None):
-    """
-    Returns a dictionary of wcskey: WCSNAME pairs
-
-    Parameters
-    ----------
-    fobj : stri, `astropy.io.fits.HDUList` or `astropy.io.fits.Header`
-          fits file name, fits file object or fits header
-    ext : int or None
-         extension number
-         if None, fobj must be a header
-
-    """
-    _check_headerpars(fobj, ext)
-    hdr = _getheader(fobj, ext)
-    names = hdr["WCSNAME*"]
-    d = {}
-    for keyword, value in names.items():
-        wkey = keyword.replace('WCSNAME','')
-        if wkey == '': wkey = ' '
-        d[wkey] = value
-    return d
-
-def available_wcskeys(fobj, ext=None):
-    """
-    Returns a list of characters which are not used in the header
-    with WCSNAME keyword. Any of them can be used to save a new
-    WCS.
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList` or `astropy.io.fits.Header`
-        fits file name, fits file object or fits header
-    ext : int or None
-        extension number
-        if None, fobj must be a header
-    """
-    _check_headerpars(fobj, ext)
-    hdr = _getheader(fobj, ext)
-    all_keys = list(string.ascii_uppercase)
-    used_keys = wcskeys(hdr)
-    try:
-        used_keys.remove(" ")
-    except ValueError:
-        pass
-    [all_keys.remove(key) for key in used_keys]
-    return all_keys
-
-def next_wcskey(fobj, ext=None):
-    """
-    Returns next available character to be used for an alternate WCS
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList` or `astropy.io.fits.Header`
-        fits file name, fits file object or fits header
-    ext : int or None
-        extension number
-        if None, fobj must be a header
-    """
-    _check_headerpars(fobj, ext)
-    hdr = _getheader(fobj, ext)
-    allkeys = available_wcskeys(hdr)
-    if allkeys != []:
-        return allkeys[0]
-    else:
-        return None
-
-def getKeyFromName(header, wcsname):
-    """
-    If WCSNAME is found in header, return its key, else return
-    None. This is used to update an alternate WCS
-    repeatedly and not generate new keys every time.
-
-    Parameters
-    ----------
-    header :  `astropy.io.fits.Header`
-    wcsname : str
-        value of WCSNAME
-    """
-    wkey = None
-    names = wcsnames(header)
-    wkeys = []
-    for item in names.items():
-        if item[1].lower() == wcsname.lower():
-            wkeys.append(item[0])
-    wkeys.sort()
-    if len(wkeys) > 0:
-        wkey = wkeys[-1]
-    else:
-        wkey = None
-    return wkey
-
-def pc2cd(hdr, key=' '):
-    """
-    Convert a CD PC matrix to a CD matrix.
-
-    WCSLIB (and PyWCS) recognizes CD keywords as input
-    but converts them and works internally with the PC matrix.
-    to_header() returns the PC matrix even if the i nput was a
-    CD matrix. To keep input and output consistent we check
-    for has_cd and convert the PC back to CD.
-
-    Parameters
-    ----------
-    hdr: `astropy.io.fits.Header`
-
-    """
-    for c in ['1_1', '1_2', '2_1', '2_2']:
-        try:
-            val = hdr['PC'+c+'%s' % key]
-            del hdr['PC'+c+ '%s' % key]
-        except KeyError:
-            if c=='1_1' or c == '2_2':
-                val = 1.
-            else:
-                val = 0.
-        #hdr.update(key='CD'+c+'%s' %key, value=val)
-        hdr['CD{0}{1}'.format(c, key)] = val
-    return hdr
-
-def _parpasscheck(fobj, ext, wcskey, fromext=None, toext=None, reusekey=False):
-    """
-    Check input parameters to altwcs functions
-
-    fobj : str or `astropy.io.fits.HDUList` object
-        a file name or a file object
-    ext : int, a tuple, a python list of integers or a python list
-        of tuples (e.g.('sci',1))
-        fits extensions to work with
-    wcskey : str
-        "A"-"Z" or " "- Used for one of 26 alternate WCS definitions
-    wcsname : str
-        (optional)
-        if given and wcskey is " ", will try to restore by WCSNAME value
-    reusekey : bool
-        A flag which indicates whether to reuse a wcskey in the header
-    """
-    if not isinstance(fobj, fits.HDUList):
-        print("First parameter must be a fits file object or a file name.")
-        return False
-
-    # first one covers the case of an object created in memory
-    # (e.g. headerlet) for which fileinfo returns None
-    if fobj.fileinfo(0) is None:
-        pass
-    else:
-        # an HDUList object with associated file
-        if fobj.fileinfo(0)['filemode'] is not 'update':
-            print("First parameter must be a file name or a file object opened in 'update' mode.")
-            return False
-
-    if not isinstance(ext, int) and not isinstance(ext, tuple) \
-        and not isinstance(ext,str) \
-        and not isinstance(ext, list) and ext is not None:
-        print("Ext must be integer, tuple, string,a list of int extension numbers, \n\
-        or a list of tuples representing a fits extension, for example ('sci', 1).")
-        return False
-
-    if not isinstance(fromext, str) and fromext is not None:
-        print("fromext must be a string representing a valid extname")
-        return False
-
-    if not isinstance(toext, list) and not isinstance(toext, str) and \
-                     toext is not None :
-        print("toext must be a string or a list of strings representing extname")
-        return False
-
-    if len(wcskey) != 1:
-        print('Parameter wcskey must be a character - one of "A"-"Z" or " "')
-        return False
-
-    return True
-
-def closefobj(fname, f):
-    """
-    Functions in this module accept as input a file name or a file object.
-    If the input was a file name (string) we close the object. If the user
-    passed a file object we leave it to the user to close it.
-    """
-    if isinstance(fname, str):
-        f.close()
-
-def mapFitsExt2HDUListInd(fname, extname):
-    """
-    Map FITS extensions with 'EXTNAME' to HDUList indexes.
-    """
-
-    if not isinstance(fname, fits.HDUList):
-        f = fits.open(fname)
-        close_file = True
-    else:
-        f = fname
-        close_file = False
-    d = {}
-    for hdu in f:
-        if 'EXTNAME' in hdu.header and hdu.header['EXTNAME'] == extname:
-            extver = hdu.header['EXTVER']
-            d[(extname, extver)] = f.index_of((extname, extver))
-    if close_file:
-        f.close()
-    return d
diff --git a/lib/stwcs/wcsutil/convertwcs.py b/lib/stwcs/wcsutil/convertwcs.py
deleted file mode 100644
index a384eb1..0000000
--- a/lib/stwcs/wcsutil/convertwcs.py
+++ /dev/null
@@ -1,118 +0,0 @@
-from __future__ import print_function
-try:
-    import stwcs
-    from stwcs import wcsutil
-except:
-    stwcs = None
-
-from stsci.tools import fileutil
-
-OPUS_WCSKEYS = ['OCRVAL1','OCRVAL2','OCRPIX1','OCRPIX2',
-                'OCD1_1','OCD1_2','OCD2_1','OCD2_2',
-                'OCTYPE1','OCTYPE2']
-
-
-def archive_prefix_OPUS_WCS(fobj,extname='SCI'):
-    """ Identifies WCS keywords which were generated by OPUS and archived
-        using a prefix of 'O' for all 'SCI' extensions in the file
-
-        Parameters
-        ----------
-        fobj : str or `astropy.io.fits.HDUList`
-            Filename or fits object of a file
-
-    """
-    if stwcs is None:
-        print('=====================')
-        print('The STWCS package is needed to convert an old-style OPUS WCS to an alternate WCS')
-        print('=====================')
-        raise ImportError
-
-
-    closefits = False
-    if isinstance(fobj,str):
-        # A filename was provided as input
-        fobj = fits.open(fobj,mode='update')
-        closefits=True
-
-    # Define the header
-    ext = ('sci',1)
-    hdr = fobj[ext].header
-
-    numextn = fileutil.countExtn(fobj)
-    extlist = []
-    for e in range(1,numextn+1):
-        extlist.append(('sci',e))
-
-    # Insure that the 'O' alternate WCS is present
-    if 'O' not in wcsutil.wcskeys(hdr):
-        # if not, archive the Primary WCS as the default OPUS WCS
-        wcsutil.archiveWCS(fobj,extlist, wcskey='O', wcsname='OPUS')
-
-    # find out how many SCI extensions are in the image
-    numextn = fileutil.countExtn(fobj,extname=extname)
-    if numextn == 0:
-        extname = 'PRIMARY'
-
-    # create HSTWCS object from PRIMARY WCS
-    wcsobj = wcsutil.HSTWCS(fobj,ext=ext,wcskey='O')
-    # get list of WCS keywords
-    wcskeys = list(wcsobj.wcs2header().keys())
-
-    # For each SCI extension...
-    for e in range(1,numextn+1):
-        # Now, look for any WCS keywords with a prefix of 'O'
-        for key in wcskeys:
-            okey = 'O'+key[:7]
-            hdr = fobj[(extname,e)].header
-            if okey in hdr:
-                # Update alternate WCS keyword with prefix-O OPUS keyword value
-                hdr[key] = hdr[okey]
-
-    if closefits:
-        fobj.close()
-
-def create_prefix_OPUS_WCS(fobj,extname='SCI'):
-    """ Creates alternate WCS with a prefix of 'O' for OPUS generated WCS values
-        to work with old MultiDrizzle.
-
-        Parameters
-        ----------
-        fobj : str or `astropy.io.fits.HDUList`
-            Filename or fits object of a file
-
-        Raises
-        ------
-        IOError:
-            if input FITS object was not opened in 'update' mode
-
-    """
-    # List of O-prefix keywords to create
-    owcskeys = OPUS_WCSKEYS
-
-    closefits = False
-    if isinstance(fobj,str):
-        # A filename was provided as input
-        fobj = fits.open(fobj, mode='update')
-        closefits=True
-    else:
-        # check to make sure this FITS obj has been opened in update mode
-        if fobj.fileinfo(0)['filemode'] != 'update':
-            print('File not opened with "mode=update". Quitting...')
-            raise IOError
-
-    # check for existance of O-prefix WCS
-    if owcskeys[0] not in fobj['sci',1].header:
-
-        # find out how many SCI extensions are in the image
-        numextn = fileutil.countExtn(fobj,extname=extname)
-        if numextn == 0:
-            extname = ''
-        for extn in range(1,numextn+1):
-            hdr = fobj[(extname,extn)].header
-            for okey in owcskeys:
-                hdr[okey] = hdr[okey[1:]+'O']
-
-    # Close FITS image if we had to open it...
-    if closefits:
-        fobj.close()
diff --git a/lib/stwcs/wcsutil/getinput.py b/lib/stwcs/wcsutil/getinput.py
deleted file mode 100644
index 8ee1123..0000000
--- a/lib/stwcs/wcsutil/getinput.py
+++ /dev/null
@@ -1,62 +0,0 @@
-from astropy.io import fits
-from stsci.tools import irafglob, fileutil, parseinput
-
-def parseSingleInput(f=None, ext=None):
-    if isinstance(f, str):
-        # create an HSTWCS object from a filename
-        if ext != None:
-            filename = f
-            if isinstance(ext,tuple):
-                if ext[0] == '':
-                    extnum = ext[1] # handle ext=('',1)
-                else:
-                    extnum = ext
-            else:
-                extnum = int(ext)
-        elif ext == None:
-            filename, ext = fileutil.parseFilename(f)
-            ext = fileutil.parseExtn(ext)
-            if ext[0] == '':
-                extnum = int(ext[1]) #handle ext=('',extnum)
-            else:
-                extnum = ext
-        phdu = fits.open(filename)
-        hdr0 = phdu[0].header
-        try:
-            ehdr = phdu[extnum].header
-        except (IndexError, KeyError) as e:
-            raise e.__class__('Unable to get extension %s.' % extnum)
-
-    elif isinstance(f, fits.HDUList):
-        phdu = f
-        if ext == None:
-            extnum = 0
-        else:
-            extnum = ext
-        ehdr = f[extnum].header
-        hdr0 = f[0].header
-        filename = hdr0.get('FILENAME', "")
-
-    else:
-        raise ValueError('Input must be a file name string or a'
-                         '`astropy.io.fits.HDUList` object')
-
-    return filename, hdr0, ehdr, phdu
-
-
-def parseMultipleInput(input):
-    if isinstance(input, str):
-        if input[0] == '@':
-            # input is an @ file
-            filelist = irafglob.irafglob(input)
-        else:
-            try:
-                filelist, output = parseinput.parseinput(input)
-            except IOError: raise
-    elif isinstance(input, list):
-        if isinstance(input[0], wcsutil.HSTWCS):
-            # a list of HSTWCS objects
-            return input
-        else:
-            filelist = input[:]
-    return filelist
diff --git a/lib/stwcs/wcsutil/headerlet.py b/lib/stwcs/wcsutil/headerlet.py
deleted file mode 100644
index c0dd9b0..0000000
--- a/lib/stwcs/wcsutil/headerlet.py
+++ /dev/null
@@ -1,2754 +0,0 @@
-"""
-This module implements headerlets.
-
-A headerlet serves as a mechanism for encapsulating WCS information
-which can be used to update the WCS solution of an image. The idea
-came up first from the desire for passing improved astrometric
-solutions for HST data and provide those solutions in a manner
-that would not require getting entirely new images from the archive
-when only the WCS information has been updated.
-
-"""
-
-from __future__ import absolute_import, division, print_function
-import os
-import sys
-import functools
-import logging
-import textwrap
-import copy
-import time
-
-import numpy as np
-from astropy.io import fits
-#import pywcs
-from astropy import wcs as pywcs
-from astropy.utils import lazyproperty
-
-from stsci.tools.fileutil import countExtn
-from stsci.tools import fileutil as fu
-from stsci.tools import parseinput
-
-from stwcs.updatewcs import utils
-from . import altwcs
-from . import wcscorr
-from .hstwcs import HSTWCS
-from .mappings import basic_wcs
-
-#### Logging support functions
-class FuncNameLoggingFormatter(logging.Formatter):
-    def __init__(self, fmt=None, datefmt=None):
-        if '%(funcName)s' not in fmt:
-            fmt = '%(funcName)s' + fmt
-        logging.Formatter.__init__(self, fmt=fmt, datefmt=datefmt)
-
-    def format(self, record):
-        record = copy.copy(record)
-        if hasattr(record, 'funcName') and record.funcName == 'init_logging':
-            record.funcName = ''
-        else:
-            record.funcName += ' '
-        return logging.Formatter.format(self, record)
-
-
-logger = logging.getLogger(__name__)
-formatter = FuncNameLoggingFormatter("%(levelname)s: %(message)s")
-ch = logging.StreamHandler()
-ch.setFormatter(formatter)
-ch.setLevel(logging.CRITICAL)
-logger.addHandler(ch)
-logger.setLevel(logging.DEBUG)
-
-FITS_STD_KW = ['XTENSION', 'BITPIX', 'NAXIS', 'PCOUNT',
-             'GCOUNT', 'EXTNAME', 'EXTVER', 'ORIGIN',
-             'INHERIT', 'DATE', 'IRAF-TLM']
-
-DEFAULT_SUMMARY_COLS = ['HDRNAME', 'WCSNAME', 'DISTNAME', 'AUTHOR', 'DATE',
-                        'SIPNAME', 'NPOLFILE', 'D2IMFILE', 'DESCRIP']
-COLUMN_DICT = {'vals': [], 'width': []}
-COLUMN_FMT = '{:<{width}}'
-
-
-def init_logging(funcname=None, level=100, mode='w', **kwargs):
-    """
-
-    Initialize logging for a function
-
-    Parameters
-    ----------
-    funcname: string
-            Name of function which will be recorded in log
-    level:  int, or bool, or string
-            int or string : Logging level
-            bool: False - switch off logging
-            Text logging level for the message ("DEBUG", "INFO",
-            "WARNING", "ERROR", "CRITICAL")
-    mode: 'w' or 'a'
-            attach to logfile ('a' or start a new logfile ('w')
-
-    """
-    for hndl in logger.handlers:
-        if isinstance(hndl, logging.FileHandler):
-            has_file_handler = True
-        else:
-            has_file_handler = False
-    if level:
-        if not has_file_handler:
-            logname = 'headerlet.log'
-            fh = logging.FileHandler(logname, mode=mode)
-            fh.setFormatter(formatter)
-            fh.setLevel(logging.DEBUG)
-            logger.addHandler(fh)
-        logger.info("%s: Starting %s with arguments:\n\t %s" %
-                    (time.asctime(), funcname, kwargs))
-
-
-def with_logging(func):
-    @functools.wraps(func)
-    def wrapped(*args, **kw):
-        level = kw.get('logging', 100)
-        mode = kw.get('logmode', 'w')
-        func_args = kw.copy()
-        if sys.version_info[0] >= 3:
-            argnames = func.__code__.co_varnames
-        else:
-            argnames = func.func_code.co_varnames
-
-        for argname, arg in zip(argnames, args):
-            func_args[argname] = arg
-
-        init_logging(func.__name__, level, mode, **func_args)
-        return func(*args, **kw)
-    return wrapped
-
-#### Utility functions
-def is_par_blank(par):
-    return par in ['', ' ', 'INDEF', "None", None]
-
-def parse_filename(fname, mode='readonly'):
-    """
-    Interprets the input as either a filename of a file that needs to be opened
-    or a PyFITS object.
-
-    Parameters
-    ----------
-    fname : str, `astropy.io.fits.HDUList`
-        Input pointing to a file or `astropy.io.fits.HDUList` object.
-        An input filename (str) will be expanded as necessary to
-        interpret any environmental variables
-        included in the filename.
-
-    mode : string
-        Specifies what mode to use when opening the file, if it needs
-        to open the file at all [Default: 'readonly']
-
-    Returns
-    -------
-    fobj : `astropy.io.fits.HDUList`
-        FITS file handle for input
-
-    fname : str
-        Name of input file
-
-    close_fobj : bool
-        Flag specifying whether or not fobj needs to be closed since it was
-        opened by this function. This allows a program to know whether they
-        need to worry about closing the FITS object as opposed to letting
-        the higher level interface close the object.
-
-    """
-    close_fobj = False
-    if not isinstance(fname, list):
-        if sys.version_info[0] >= 3:
-            is_string = isinstance(fname, str)
-        else:
-            is_string = isinstance(fname, basestring)
-        if is_string:
-            fname = fu.osfn(fname)
-        fobj = fits.open(fname, mode=mode)
-        close_fobj = True
-    else:
-        fobj = fname
-        if hasattr(fobj, 'filename'):
-            fname = fobj.filename()
-        else:
-            fname = ''
-    return fobj, fname, close_fobj
-
-def get_headerlet_kw_names(fobj, kw='HDRNAME'):
-    """
-    Returns a list of specified keywords from all HeaderletHDU
-    extensions in a science file.
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList`
-    kw : str
-        Name of keyword to be read and reported
-    """
-
-    fobj, fname, open_fobj = parse_filename(fobj)
-
-    hdrnames = []
-    for ext in fobj:
-        if isinstance(ext, fits.hdu.base.NonstandardExtHDU):
-            hdrnames.append(ext.header[kw])
-
-    if open_fobj:
-        fobj.close()
-
-    return hdrnames
-
-def get_header_kw_vals(hdr, kwname, kwval, default=0):
-    if kwval is None:
-        if kwname in hdr:
-            kwval = hdr[kwname]
-        else:
-            kwval = default
-    return kwval
-
-@with_logging
-def find_headerlet_HDUs(fobj, hdrext=None, hdrname=None, distname=None,
-                        strict=True, logging=False, logmode='w'):
-    """
-    Returns all HeaderletHDU extensions in a science file that matches
-    the inputs specified by the user.  If no hdrext, hdrname or distname are
-    specified, this function will return a list of all HeaderletHDU objects.
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList`
-        Name of FITS file or open fits object (`astropy.io.fits.HDUList` instance)
-    hdrext : int, tuple or None
-        index number(EXTVER) or extension tuple of HeaderletHDU to be returned
-    hdrname : string
-        value of HDRNAME for HeaderletHDU to be returned
-    distname : string
-        value of DISTNAME for HeaderletHDUs to be returned
-    strict : bool [Default: True]
-        Specifies whether or not at least one parameter needs to be provided
-        If False, all extension indices returned if hdrext, hdrname and distname
-        are all None. If True and hdrext, hdrname, and distname are all None,
-        raise an Exception requiring one to be specified.
-    logging : boolean
-             enable logging to a file called headerlet.log
-    logmode : 'w' or 'a'
-             log file open mode
-
-    Returns
-    -------
-    hdrlets : list
-        A list of all matching HeaderletHDU extension indices (could be just one)
-
-    """
-
-    get_all = False
-    if hdrext is None and hdrname is None and distname is None:
-        if not strict:
-            get_all = True
-        else:
-            mess = """\n
-            =====================================================
-            No valid Headerlet extension specified.
-            Either "hdrname", "hdrext", or "distname" needs to be specified.
-            =====================================================
-            """
-            logger.critical(mess)
-            raise ValueError
-
-    fobj, fname, open_fobj = parse_filename(fobj)
-
-    hdrlets = []
-    if hdrext is not None and isinstance(hdrext, int):
-        if hdrext in range(len(fobj)): # insure specified hdrext is in fobj
-            if isinstance(fobj[hdrext], fits.hdu.base.NonstandardExtHDU) and \
-                fobj[hdrext].header['EXTNAME'] == 'HDRLET':
-                hdrlets.append(hdrext)
-    else:
-        for ext in fobj:
-            if isinstance(ext, fits.hdu.base.NonstandardExtHDU):
-                if get_all:
-                    hdrlets.append(fobj.index(ext))
-                else:
-                    if hdrext is not None:
-                        if isinstance(hdrext, tuple):
-                            hdrextname = hdrext[0]
-                            hdrextnum = hdrext[1]
-                        else:
-                            hdrextname = 'HDRLET'
-                            hdrextnum = hdrext
-                    hdrext_match = ((hdrext is not None) and
-                                    (hdrextnum == ext.header['EXTVER']) and
-                                    (hdrextname == ext.header['EXTNAME']))
-                    hdrname_match = ((hdrname is not None) and
-                                        (hdrname == ext.header['HDRNAME']))
-                    distname_match = ((distname is not None) and
-                                        (distname == ext.header['DISTNAME']))
-                    if hdrext_match or hdrname_match or distname_match:
-                        hdrlets.append(fobj.index(ext))
-
-    if open_fobj:
-        fobj.close()
-
-    if len(hdrlets) == 0:
-        if hdrname:
-            kwerr = 'hdrname'
-            kwval = hdrname
-        elif hdrext:
-            kwerr = 'hdrext'
-            kwval = hdrext
-        else:
-            kwerr = 'distname'
-            kwval = distname
-        message = """\n
-        =====================================================
-        No valid Headerlet extension found!'
-        "%s" = %s not found in %s.' % (kwerr, kwval, fname)
-        =====================================================
-        """
-        logger.critical(message)
-        raise ValueError
-
-    return hdrlets
-
-def verify_hdrname_is_unique(fobj, hdrname):
-    """
-    Verifies that no other HeaderletHDU extension has the specified hdrname.
-
-    Parameters
-    ----------
-    fobj : str, `astropy.io.fits.HDUList`
-        Name of FITS file or open fits file object
-    hdrname : str
-        value of HDRNAME for HeaderletHDU to be compared as unique
-
-    Returns
-    -------
-    unique: bool
-        If True, no other HeaderletHDU has the specified HDRNAME value
-    """
-    hdrnames_list = get_headerlet_kw_names(fobj)
-    unique = not(hdrname in hdrnames_list)
-
-    return unique
-
-def update_versions(sourcehdr, desthdr):
-    """
-    Update keywords which store version numbers
-    """
-    phdukw = {'PYWCSVER': 'Version of PYWCS used to updated the WCS',
-              'UPWCSVER': 'Version of STWCS used to updated the WCS'
-              }
-    for key in phdukw:
-        try:
-            desthdr[key] = (sourcehdr[key], sourcehdr.comments[key])
-        except KeyError:
-            desthdr[key] = (" ", phdukw[key])
-
-def update_ref_files(source, dest):
-    """
-    Update the reference files name in the primary header of 'dest'
-    using values from 'source'
-
-    Parameters
-    ----------
-    source : `astropy.io.fits.Header`
-    dest :   `astropy.io.fits.Header`
-    """
-    logger.info("Updating reference files")
-    phdukw = {'NPOLFILE': True,
-              'IDCTAB': True,
-              'D2IMFILE': True,
-              'SIPNAME': True,
-              'DISTNAME': True}
-
-    for key in phdukw:
-        try:
-            try:
-                del dest[key]
-            except:
-                pass
-            dest.set(key, source[key], source.comments[key])
-        except KeyError:
-            phdukw[key] = False
-    return phdukw
-
-def print_summary(summary_cols, summary_dict, pad=2, maxwidth=None, idcol=None,
-                    output=None, clobber=True, quiet=False ):
-    """
-    Print out summary dictionary to STDOUT, and possibly an output file
-
-    """
-    nrows = None
-    if idcol:
-        nrows = len(idcol['vals'])
-
-    # Find max width of each column
-    column_widths = {}
-    for kw in summary_dict:
-        colwidth = np.array(summary_dict[kw]['width']).max()
-        if maxwidth:
-            colwidth = min(colwidth, maxwidth)
-        column_widths[kw] = colwidth + pad
-        if nrows is None:
-            nrows = len(summary_dict[kw]['vals'])
-
-    # print rows now
-    outstr = ''
-    # Start with column names
-    if idcol:
-        outstr += COLUMN_FMT.format(idcol['name'], width=idcol['width'] + pad)
-    for kw in summary_cols:
-        outstr += COLUMN_FMT.format(kw, width=column_widths[kw])
-    outstr += '\n'
-    # Now, add a row for each headerlet
-    for row in range(nrows):
-        if idcol:
-            outstr += COLUMN_FMT.format(idcol['vals'][row],
-                                        width=idcol['width']+pad)
-        for kw in summary_cols:
-            val = summary_dict[kw]['vals'][row][:(column_widths[kw]-pad)]
-            outstr += COLUMN_FMT.format(val, width=column_widths[kw])
-        outstr += '\n'
-    if not quiet:
-        print(outstr)
-
-    # If specified, write info to separate text file
-    write_file = False
-    if output:
-        output = fu.osfn(output) # Expand any environment variables in filename
-        write_file = True
-        if os.path.exists(output):
-            if clobber:
-                os.remove(output)
-            else:
-                print('WARNING: Not writing results to file!')
-                print('         Output text file ', output, ' already exists.')
-                print('         Set "clobber" to True or move file before trying again.')
-                write_file = False
-        if write_file:
-            fout = open(output, mode='w')
-            fout.write(outstr)
-            fout.close()
-
-#### Private utility functions
-def _create_primary_HDU(fobj, fname, wcsext, destim, hdrname, wcsname,
-                            sipname, npolfile, d2imfile,
-                            nmatch,catalog, wcskey,
-                            author, descrip, history):
-    # convert input values into valid FITS kw values
-    if author is None:
-        author = ''
-    if descrip is None:
-        descrip = ''
-
-    sipname, idctab = utils.build_sipname(fobj, fname, sipname)
-    logger.info("Setting sipname value to %s" % sipname)
-
-    npolname, npolfile = utils.build_npolname(fobj, npolfile)
-    logger.info("Setting npolfile value to %s" % npolname)
-
-    d2imname, d2imfile = utils.build_d2imname(fobj,d2imfile)
-    logger.info("Setting d2imfile value to %s" % d2imname)
-
-    distname = utils.build_distname(sipname, npolname, d2imname)
-    logger.info("Setting distname to %s" % distname)
-
-    # open file and parse comments
-    if history not in ['', ' ', None, 'INDEF'] and os.path.isfile(history):
-        f = open(fu.osfn(history))
-        history = f.readlines()
-        f.close()
-    else:
-        history = ''
-
-    rms_ra = fobj[wcsext].header.get("CRDER1"+wcskey, 0)
-    rms_dec = fobj[wcsext].header.get("CRDER2"+wcskey, 0)
-    if not nmatch:
-        nmatch = fobj[wcsext].header.get("NMATCH"+wcskey, 0)
-    if not catalog:
-        catalog = fobj[wcsext].header.get('CATALOG'+wcskey, "")
-    # get the version of STWCS used to create the WCS of the science file.
-    #try:
-        #upwcsver = fobj[0].header.cards[fobj[0].header.index('UPWCSVER')]
-    #except KeyError:
-        #upwcsver = pyfits.Card("UPWCSVER", " ",
-                               #"Version of STWCS used to update the WCS")
-    #try:
-        #pywcsver = fobj[0].header.cards[fobj[0].header.index('PYWCSVER')]
-    #except KeyError:
-        #pywcsver = pyfits.Card("PYWCSVER", " ",
-                               #"Version of PYWCS used to update the WCS")
-    upwcsver = fobj[0].header.get('UPWCSVER', "")
-    pywcsver = fobj[0].header.get('PYWCSVER', "")
-    # build Primary HDU
-    phdu = fits.PrimaryHDU()
-    phdu.header['DESTIM'] = (destim, 'Destination observation root name')
-    phdu.header['HDRNAME'] = (hdrname, 'Headerlet name')
-    fmt = "%Y-%m-%dT%H:%M:%S"
-    phdu.header['DATE'] = (time.strftime(fmt), 'Date FITS file was generated')
-    phdu.header['WCSNAME'] = (wcsname, 'WCS name')
-    phdu.header['DISTNAME'] = (distname, 'Distortion model name')
-    phdu.header['SIPNAME'] = (sipname,
-                              'origin of SIP polynomial distortion model')
-    phdu.header['NPOLFILE'] = (npolfile,
-                               'origin of non-polynmial distortion model')
-    phdu.header['D2IMFILE'] = (d2imfile,
-                               'origin of detector to image correction')
-    phdu.header['IDCTAB'] = (idctab,
-                               'origin of Polynomial Distortion')
-    phdu.header['AUTHOR'] = (author, 'headerlet created by this user')
-    phdu.header['DESCRIP'] = (descrip,
-                              'Short description of headerlet solution')
-    phdu.header['RMS_RA'] = (rms_ra,
-                             'RMS in RA at ref pix of headerlet solution')
-    phdu.header['RMS_DEC'] = (rms_dec,
-                              'RMS in Dec at ref pix of headerlet solution')
-    phdu.header['NMATCH'] = (nmatch,
-                             'Number of sources used for headerlet solution')
-    phdu.header['CATALOG'] = (catalog,
-                              'Astrometric catalog used for headerlet '
-                              'solution')
-    phdu.header['UPWCSVER'] = (upwcsver, "Version of STWCS used to update the WCS")
-    phdu.header['PYWCSVER'] = (pywcsver, "Version of PYWCS used to update the WCS")
-
-    # clean up history string in order to remove whitespace characters that
-    # would cause problems with FITS
-    if isinstance(history, list):
-        history_str = ''
-        for line in history:
-            history_str += line
-    else:
-        history_str = history
-    history_lines = textwrap.wrap(history_str, width=70)
-    for hline in history_lines:
-        phdu.header.add_history(hline)
-
-    return phdu
-
-
-#### Public Interface functions
-@with_logging
-def extract_headerlet(filename, output, extnum=None, hdrname=None,
-                      clobber=False, logging=True):
-    """
-    Finds a headerlet extension in a science file and writes it out as
-    a headerlet FITS file.
-
-    If both hdrname and extnum are given they should match, if not
-    raise an Exception
-
-    Parameters
-    ----------
-    filename: string or HDUList or Python list
-        This specifies the name(s) of science file(s) from which headerlets
-        will be extracted.
-
-        String input formats supported include use of wild-cards, IRAF-style
-        '@'-files (given as '@<filename>') and comma-separated list of names.
-        An input filename (str) will be expanded as necessary to interpret
-        any environmental variables included in the filename.
-        If a list of filenames has been specified, it will extract a
-        headerlet from the same extnum from all filenames.
-    output: string
-           Filename or just rootname of output headerlet FITS file
-           If string does not contain '.fits', it will create a filename with
-           '_hlet.fits' suffix
-    extnum: int
-           Extension number which contains the headerlet to be written out
-    hdrname: string
-           Unique name for headerlet, stored as the HDRNAME keyword
-           It stops if a value is not provided and no extnum has been specified
-    clobber: bool
-        If output file already exists, this parameter specifies whether or not
-        to overwrite that file [Default: False]
-    logging: boolean
-             enable logging to a file
-
-    """
-
-    if isinstance(filename, fits.HDUList):
-        filename = [filename]
-    else:
-        filename, oname = parseinput.parseinput(filename)
-
-    for f in filename:
-        fobj, fname, close_fobj = parse_filename(f)
-        frootname = fu.buildNewRootname(fname)
-        if hdrname in ['', ' ', None, 'INDEF'] and extnum is None:
-            if close_fobj:
-                fobj.close()
-                logger.critical("Expected a valid extnum or hdrname parameter")
-                raise ValueError
-        if hdrname is not None:
-            extn_from_hdrname = find_headerlet_HDUs(fobj, hdrname=hdrname)[0]
-            if extn_from_hdrname != extnum:
-                logger.critical("hdrname and extnmu should refer to the same FITS extension")
-                raise ValueError
-            else:
-                hdrhdu = fobj[extn_from_hdrname]
-        else:
-            hdrhdu = fobj[extnum]
-
-        if not isinstance(hdrhdu, HeaderletHDU):
-            logger.critical("Specified extension is not a headerlet")
-            raise ValueError
-
-        hdrlet = hdrhdu.headerlet
-
-        if output is None:
-            output = frootname
-
-        if '.fits' in output:
-            outname = output
-        else:
-            outname = '%s_hlet.fits' % output
-
-        hdrlet.tofile(outname, clobber=clobber)
-
-        if close_fobj:
-            fobj.close()
-
-
-@with_logging
-def write_headerlet(filename, hdrname, output=None, sciext='SCI',
-                        wcsname=None, wcskey=None, destim=None,
-                        sipname=None, npolfile=None, d2imfile=None,
-                        author=None, descrip=None, history=None,
-                        nmatch=None, catalog=None,
-                        attach=True, clobber=False, logging=False):
-
-    """
-    Save a WCS as a headerlet FITS file.
-
-    This function will create a headerlet, write out the headerlet to a
-    separate headerlet file, then, optionally, attach it as an extension
-    to the science image (if it has not already been archived)
-
-    Either wcsname or wcskey must be provided; if both are given, they must
-    match a valid WCS.
-
-    Updates wcscorr if necessary.
-
-    Parameters
-    ----------
-    filename: string or HDUList or Python list
-        This specifies the name(s) of science file(s) from which headerlets
-        will be created and written out.
-        String input formats supported include use of wild-cards, IRAF-style
-        '@'-files (given as '@<filename>') and comma-separated list of names.
-        An input filename (str) will be expanded as necessary to interpret
-        any environmental variables included in the filename.
-    hdrname: string
-        Unique name for this headerlet, stored as HDRNAME keyword
-    output: string or None
-        Filename or just rootname of output headerlet FITS file
-        If string does not contain '.fits', it will create a filename
-        starting with the science filename and ending with '_hlet.fits'.
-        If None, a default filename based on the input filename will be
-        generated for the headerlet FITS filename
-    sciext: string
-        name (EXTNAME) of extension that contains WCS to be saved
-    wcsname: string
-        name of WCS to be archived, if " ": stop
-    wcskey: one of A...Z or " " or "PRIMARY"
-        if " " or "PRIMARY" - archive the primary WCS
-    destim: string
-        DESTIM keyword
-        if  NOne, use ROOTNAME or science file name
-    sipname: string or None (default)
-         Name of unique file where the polynomial distortion coefficients were
-         read from. If None, the behavior is:
-         The code looks for a keyword 'SIPNAME' in the science header
-         If not found, for HST it defaults to 'IDCTAB'
-         If there is no SIP model the value is 'NOMODEL'
-         If there is a SIP model but no SIPNAME, it is set to 'UNKNOWN'
-    npolfile: string or None (default)
-         Name of a unique file where the non-polynomial distortion was stored.
-         If None:
-         The code looks for 'NPOLFILE' in science header.
-         If 'NPOLFILE' was not found and there is no npol model, it is set to 'NOMODEL'
-         If npol model exists, it is set to 'UNKNOWN'
-    d2imfile: string
-         Name of a unique file where the detector to image correction was
-         stored. If None:
-         The code looks for 'D2IMFILE' in the science header.
-         If 'D2IMFILE' is not found and there is no d2im correction,
-         it is set to 'NOMODEL'
-         If d2im correction exists, but 'D2IMFILE' is missing from science
-         header, it is set to 'UNKNOWN'
-    author: string
-        Name of user who created the headerlet, added as 'AUTHOR' keyword
-        to headerlet PRIMARY header
-    descrip: string
-        Short description of the solution provided by the headerlet
-        This description will be added as the single 'DESCRIP' keyword
-        to the headerlet PRIMARY header
-    history: filename, string or list of strings
-        Long (possibly multi-line) description of the solution provided
-        by the headerlet. These comments will be added as 'HISTORY' cards
-        to the headerlet PRIMARY header
-        If filename is specified, it will format and attach all text from
-        that file as the history.
-    attach: bool
-        Specify whether or not to attach this headerlet as a new extension
-        It will verify that no other headerlet extension has been created with
-        the same 'hdrname' value.
-    clobber: bool
-        If output file already exists, this parameter specifies whether or not
-        to overwrite that file [Default: False]
-    logging: boolean
-         enable file logging
-    """
-
-    if isinstance(filename, fits.HDUList):
-        filename = [filename]
-    else:
-        filename, oname = parseinput.parseinput(filename)
-
-    for f in filename:
-        if isinstance(f, str):
-            fname = f
-        else:
-            fname = f.filename()
-
-        if wcsname in [None, ' ', '', 'INDEF'] and wcskey is None:
-            message = """\n
-            No valid WCS found found in %s.
-            A valid value for either "wcsname" or "wcskey"
-            needs to be specified.
-            """ % fname
-            logger.critical(message)
-            raise ValueError
-
-        # Translate 'wcskey' value for PRIMARY WCS to valid altwcs value of ' '
-        if wcskey == 'PRIMARY':
-            wcskey = ' '
-
-        if attach:
-            umode = 'update'
-        else:
-            umode = 'readonly'
-
-        fobj, fname, close_fobj = parse_filename(f, mode=umode)
-
-        # Interpret sciext input for this file
-        if isinstance(sciext, int):
-            sciextlist = [sciext] # allow for specification of simple FITS header
-        elif isinstance(sciext, str):
-            numsciext = countExtn(fobj, sciext)
-            if numsciext > 0:
-                sciextlist = [tuple((sciext,i)) for i in range(1, numsciext+1)]
-            else:
-                sciextlist = [0]
-        elif isinstance(sciext, list):
-            sciextlist = sciext
-        else:
-            errstr = "Expected sciext to be a list of FITS extensions with science data\n"+\
-                  "    a valid EXTNAME string, or an integer."
-            logger.critical(errstr)
-            raise ValueError
-
-        wnames = altwcs.wcsnames(fobj,ext=sciextlist[0])
-
-        # Insure that WCSCORR table has been created with all original
-        # WCS's recorded prior to adding the headerlet WCS
-        wcscorr.init_wcscorr(fobj)
-
-        if wcsname is None:
-            scihdr = fobj[sciextlist[0]].header
-            wname = scihdr['wcsname'+wcskey]
-        else:
-            wname = wcsname
-        if hdrname in [None, ' ', '']:
-            hdrname = wcsname
-
-        logger.critical('Creating the headerlet from image %s' % fname)
-        hdrletobj = create_headerlet(fobj, sciext=sciextlist,
-                                    wcsname=wname, wcskey=wcskey,
-                                    hdrname=hdrname,
-                                    sipname=sipname, npolfile=npolfile,
-                                    d2imfile=d2imfile, author=author,
-                                    descrip=descrip, history=history,
-                                    nmatch=nmatch, catalog=catalog,
-                                    logging=False)
-
-        if attach:
-            # Check to see whether or not a HeaderletHDU with
-            #this hdrname already exists
-            hdrnames = get_headerlet_kw_names(fobj)
-            if hdrname not in hdrnames:
-                hdrlet_hdu = HeaderletHDU.fromheaderlet(hdrletobj)
-
-                if destim is not None:
-                    hdrlet_hdu.header['destim'] = destim
-
-                fobj.append(hdrlet_hdu)
-
-                # Update the WCSCORR table with new rows from the headerlet's WCSs
-                wcscorr.update_wcscorr(fobj, source=hdrletobj,
-                                       extname='SIPWCS', wcs_id=wname)
-
-                utils.updateNEXTENDKw(fobj)
-                fobj.flush()
-            else:
-                message = """
-                Headerlet with hdrname %s already archived for WCS %s.
-                No new headerlet appended to %s.
-                """ % (hdrname, wname, fname)
-                logger.critical(message)
-
-        if close_fobj:
-            logger.info('Closing image in write_headerlet()...')
-            fobj.close()
-
-        frootname = fu.buildNewRootname(fname)
-
-        if output is None:
-            # Generate default filename for headerlet FITS file
-            outname = '{0}_hlet.fits'.format(frootname)
-        else:
-            outname = output
-
-        if not outname.endswith('.fits'):
-            outname = '{0}_{1}_hlet.fits'.format(frootname,outname)
-
-        # If user specifies an output filename for headerlet, write it out
-        hdrletobj.tofile(outname, clobber=clobber)
-        logger.critical( 'Created Headerlet file %s ' % outname)
-
-        del hdrletobj
-
-@with_logging
-def create_headerlet(filename, sciext='SCI', hdrname=None, destim=None,
-                     wcskey=" ", wcsname=None,
-                     sipname=None, npolfile=None, d2imfile=None,
-                     author=None, descrip=None, history=None,
-                     nmatch=None, catalog=None,
-                     logging=False, logmode='w'):
-    """
-    Create a headerlet from a WCS in a science file
-    If both wcskey and wcsname are given they should match, if not
-    raise an Exception
-
-    Parameters
-    ----------
-    filename: string or HDUList
-            Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    sciext: string or python list (default: 'SCI')
-            Extension in which the science data with the linear WCS is.
-            The headerlet will be created from these extensions.
-            If string - a valid EXTNAME is expected
-            If int - specifies an extension with a valid WCS, such as 0 for a
-            simple FITS file
-            If list - a list of FITS extension numbers or strings representing
-            extension tuples, e.g. ('SCI, 1') is expected.
-    hdrname: string
-            value of HDRNAME keyword
-            Takes the value from the HDRNAME<wcskey> keyword, if not available from WCSNAME<wcskey>
-            It stops if neither is found in the science file and a value is not provided
-    destim: string or None
-            name of file this headerlet can be applied to
-            if None, use ROOTNAME keyword
-    wcskey: char (A...Z) or " " or "PRIMARY" or None
-            a char representing an alternate WCS to be used for the headerlet
-            if " ", use the primary (default)
-            if None use wcsname
-    wcsname: string or None
-            if wcskey is None use wcsname specified here to choose an alternate WCS for the headerlet
-    sipname: string or None (default)
-            Name of unique file where the polynomial distortion coefficients were
-            read from. If None, the behavior is:
-            The code looks for a keyword 'SIPNAME' in the science header
-            If not found, for HST it defaults to 'IDCTAB'
-            If there is no SIP model the value is 'NOMODEL'
-            If there is a SIP model but no SIPNAME, it is set to 'UNKNOWN'
-    npolfile: string or None (default)
-            Name of a unique file where the non-polynomial distortion was stored.
-            If None:
-            The code looks for 'NPOLFILE' in science header.
-            If 'NPOLFILE' was not found and there is no npol model, it is set to 'NOMODEL'
-            If npol model exists, it is set to 'UNKNOWN'
-    d2imfile: string
-            Name of a unique file where the detector to image correction was
-            If None:
-            The code looks for 'D2IMFILE' in the science header.
-            If 'D2IMFILE' is not found and there is no d2im correction,
-            it is set to 'NOMODEL'
-            If d2im correction exists, but 'D2IMFILE' is missing from science
-            header, it is set to 'UNKNOWN'
-    author: string
-            Name of user who created the headerlet, added as 'AUTHOR' keyword
-            to headerlet PRIMARY header
-    descrip: string
-            Short description of the solution provided by the headerlet
-            This description will be added as the single 'DESCRIP' keyword
-            to the headerlet PRIMARY header
-    history: filename, string or list of strings
-            Long (possibly multi-line) description of the solution provided
-            by the headerlet. These comments will be added as 'HISTORY' cards
-            to the headerlet PRIMARY header
-            If filename is specified, it will format and attach all text from
-            that file as the history.
-    nmatch: int (optional)
-            Number of sources used in the new solution fit
-    catalog: string (optional)
-            Astrometric catalog used for headerlet solution
-    logging: boolean
-            enable file logging
-    logmode: 'w' or 'a'
-            log file open mode
-
-    Returns
-    -------
-    Headerlet object
-
-    """
-    if wcskey == 'O':
-        message = "Warning: 'O' is a reserved key for the original WCS. Quitting..."
-        logger.info(message)
-        return None
-
-    fobj, fname, close_file = parse_filename(filename)
-    # based on `sciext` create a list of (EXTNAME, EXTVER) tuples
-    # of extensions with WCS to be saved in a headerlet
-    sciext = get_extname_extver_list(fobj, sciext)
-    logger.debug("Data extensions from which to create headerlet:\n\t %s"
-                 % (str(sciext)))
-    if not sciext:
-        logger.critical("No valid target extensions found in file %s" % fname)
-        raise ValueError
-
-    # Define extension to evaluate for verification of input parameters
-    wcsext = sciext[0]
-    logger.debug("sciext in create_headerlet is %s" % str(sciext))
-    # Translate 'wcskey' value for PRIMARY WCS to valid altwcs value of ' '
-    if wcskey == 'PRIMARY':
-        wcskey = ' '
-        logger.info("wcskey reset from 'PRIMARY' to ' '")
-    wcskey = wcskey.upper()
-    wcsnamekw = "".join(["WCSNAME", wcskey.upper()]).rstrip()
-    hdrnamekw = "".join(["HDRNAME", wcskey.upper()]).rstrip()
-
-    wnames = altwcs.wcsnames(fobj, ext=wcsext)
-    if not wcsname:
-        # User did not specify a value for 'wcsname'
-        if wcsnamekw in fobj[wcsext].header:
-            #check if there's a WCSNAME for this wcskey in the header
-            wcsname = fobj[wcsext].header[wcsnamekw]
-            logger.info("Setting wcsname from header[%s] to %s" % (wcsnamekw, wcsname))
-        else:
-            if hdrname not in ['', ' ', None, "INDEF"]:
-                """
-                If wcsname for this wcskey was not provided
-                and WCSNAME<wcskey> does not exist in the header
-                and hdrname is provided, then
-                use hdrname as WCSNAME for the headerlet.
-                """
-                wcsname = hdrname
-                logger.debug("Setting wcsname from hdrname to %s" % hdrname)
-            else:
-                if hdrnamekw in fobj[wcsext].header:
-                    wcsname = fobj[wcsext].header[hdrnamekw]
-                    logger.debug("Setting wcsname from header[%s] to %s" % (hdrnamekw, wcsname))
-                else:
-                    message = """
-                    Required keywords 'HDRNAME' or 'WCSNAME' not found!
-                    Please specify a value for parameter 'hdrname'
-                    or update header with 'WCSNAME' keyword.
-                    """
-                    logger.critical(message)
-                    raise KeyError
-    else:
-        # Verify that 'wcsname' and 'wcskey' values specified by user reference
-        # the same WCS
-        wname = fobj[wcsext].header[wcsnamekw]
-        if wcsname != wname:
-            message = "\tInconsistent values for 'wcskey' and 'wcsname' specified!\n"
-            message += "    'wcskey' = %s and 'wcsname' = %s. \n" % (wcskey, wcsname)
-            message += "Actual value of %s found to be %s. \n" % (wcsnamekw, wname)
-            logger.critical(message)
-            raise KeyError
-    wkeys = altwcs.wcskeys(fobj, ext=wcsext)
-    if wcskey != ' ':
-        if wcskey not in wkeys:
-            logger.critical('No WCS with wcskey=%s found in extension %s.  Skipping...' % (wcskey, str(wcsext)))
-            raise ValueError("No WCS with wcskey=%s found in extension %s.  Skipping...' % (wcskey, str(wcsext))")
-
-    # get remaining required keywords
-    if destim is None:
-        if 'ROOTNAME' in fobj[0].header:
-            destim = fobj[0].header['ROOTNAME']
-            logger.info("Setting destim to rootname of the science file")
-        else:
-            destim = fname
-            logger.info('DESTIM not provided')
-            logger.info('Keyword "ROOTNAME" not found')
-            logger.info('Using file name as DESTIM')
-
-    if not hdrname:
-        # check if HDRNAME<wcskey> is in header
-        if hdrnamekw in fobj[wcsext].header:
-            hdrname = fobj[wcsext].header[hdrnamekw]
-        else:
-            if wcsnamekw in fobj[wcsext].header:
-                hdrname = fobj[wcsext].header[wcsnamekw]
-                message = """
-                Using default value for HDRNAME of "%s" derived from %s.
-                """ % (hdrname, wcsnamekw)
-                logger.info(message)
-                logger.info("Setting hdrname to %s from header[%s]"
-                            % (hdrname, wcsnamekw))
-            else:
-                message = "Required keywords 'HDRNAME' or 'WCSNAME' not found"
-                logger.critical(message)
-                raise KeyError
-
-
-
-    hdul = []
-    phdu = _create_primary_HDU(fobj, fname, wcsext, destim, hdrname, wcsname,
-                             sipname, npolfile, d2imfile,
-                             nmatch, catalog, wcskey,
-                             author, descrip, history)
-    hdul.append(phdu)
-    wcsdvarr_extns = []
-    """
-    nd2i is a counter for d2i extensions to be used when the science file
-    has an old d2i correction format. The old format did not write EXTVER
-    kw for the d2i correction in the science header bu tthe new format expects
-    them.
-    """
-    nd2i_extver = 1
-    for ext in sciext:
-        wkeys = altwcs.wcskeys(fobj, ext=ext)
-        if wcskey != ' ':
-            if wcskey not in wkeys:
-                logger.debug(
-                    'No WCS with wcskey=%s found in extension %s.  '
-                    'Skipping...' % (wcskey, str(ext)))
-                raise ValueError("")
-
-        hwcs = HSTWCS(fobj, ext=ext, wcskey=wcskey)
-
-        whdul = hwcs.to_fits(relax=True, key=" ")
-        if hasattr(hwcs, 'orientat'):
-            orient_comment = "positions angle of image y axis (deg. e of n)"
-            whdul[0].header['ORIENTAT'] = (hwcs.orientat, orient_comment)
-
-        whdul[0].header.append(('TG_ENAME', ext[0], 'Target science data extname'))
-        whdul[0].header.append(('TG_EVER', ext[1], 'Target science data extver'))
-
-        if hwcs.wcs.has_cd():
-            whdul[0].header = altwcs.pc2cd(whdul[0].header)
-
-        idckw = hwcs._idc2hdr()
-        whdul[0].header.extend(idckw)
-
-        if hwcs.det2im1 or hwcs.det2im2:
-            try:
-                whdul[0].header.append(fobj[ext].header.cards['D2IMEXT'])
-            except KeyError:
-                pass
-            whdul[0].header.extend(fobj[ext].header.cards['D2IMERR*'])
-            if 'D2IM1.EXTVER' in whdul[0].header:
-                try:
-                    whdul[0].header['D2IM1.EXTVER'] = fobj[ext].header['D2IM1.EXTVER']
-                except KeyError:
-                    whdul[0].header['D2IM1.EXTVER'] = nd2i_extver
-                    nd2i_extver += 1
-            if 'D2IM2.EXTVER' in whdul[0].header:
-                try:
-                    whdul[0].header['D2IM2.EXTVER'] = fobj[ext].header['D2IM2.EXTVER']
-                except KeyError:
-                    whdul[0].header['D2IM2.EXTVER'] = nd2i_extver
-                    nd2i_extver += 1
-
-        if hwcs.cpdis1 or hwcs.cpdis2:
-            whdul[0].header.extend(fobj[ext].header.cards['CPERR*'])
-            try:
-                whdul[0].header.append(fobj[ext].header.cards['NPOLEXT'])
-            except KeyError:
-                pass
-            if 'DP1.EXTVER' in whdul[0].header:
-                whdul[0].header['DP1.EXTVER'] = fobj[ext].header['DP1.EXTVER']
-            if 'DP2.EXTVER' in whdul[0].header:
-                whdul[0].header['DP2.EXTVER'] = fobj[ext].header['DP2.EXTVER']
-        ihdu = fits.ImageHDU(header=whdul[0].header, name='SIPWCS')
-
-        if ext[0] != "PRIMARY":
-            ihdu.update_ext_version(fobj[ext].header['EXTVER'], comment='Extension version')
-
-        hdul.append(ihdu)
-
-        if hwcs.cpdis1:
-            whdu = whdul[('WCSDVARR', 1)].copy()
-            whdu.update_ext_version(fobj[ext].header['DP1.EXTVER'])
-            hdul.append(whdu)
-        if hwcs.cpdis2:
-            whdu = whdul[('WCSDVARR', 2)].copy()
-            whdu.update_ext_version(fobj[ext].header['DP2.EXTVER'])
-            hdul.append(whdu)
-
-        if hwcs.det2im1:
-            whdu = whdul[('D2IMARR', 1)].copy()
-            whdu.update_ext_version(ihdu.header['D2IM1.EXTVER'])
-            hdul.append(whdu)
-        if hwcs.det2im2:
-            whdu = whdul[('D2IMARR', 2)].copy()
-            whdu.update_ext_version(ihdu.header['D2IM2.EXTVER'])
-            hdul.append(whdu)
-
-
-        #if hwcs.det2im1 or hwcs.det2im2:
-            #try:
-                #darr = hdul[('D2IMARR', 1)]
-            #except KeyError:
-                #whdu = whdul[('D2IMARR')]
-                #whdu.update_ext_version(1)
-                #hdul.append(whdu)
-    if close_file:
-        fobj.close()
-
-    hlet = Headerlet(hdul, logging=logging, logmode='a')
-    hlet.init_attrs()
-    return hlet
-
-@with_logging
-def apply_headerlet_as_primary(filename, hdrlet, attach=True, archive=True,
-                                force=False, logging=False, logmode='a'):
-    """
-    Apply headerlet 'hdrfile' to a science observation 'destfile' as the primary WCS
-
-    Parameters
-    ----------
-    filename: string or list of strings
-             File name(s) of science observation whose WCS solution will be updated
-    hdrlet: string or list of strings
-             Headerlet file(s), must match 1-to-1 with input filename(s)
-    attach: boolean
-            True (default): append headerlet to FITS file as a new extension.
-    archive: boolean
-            True (default): before updating, create a headerlet with the
-            WCS old solution.
-    force: boolean
-            If True, this will cause the headerlet to replace the current PRIMARY
-            WCS even if it has a different distortion model. [Default: False]
-    logging: boolean
-            enable file logging
-    logmode: 'w' or 'a'
-             log file open mode
-    """
-    if not isinstance(filename, list):
-        filename = [filename]
-    if not isinstance(hdrlet, list):
-        hdrlet = [hdrlet]
-    if len(hdrlet) != len(filename):
-        logger.critical("Filenames must have matching headerlets. "
-                "{0:d} filenames and {1:d} headerlets specified".format(len(filename),len(hdrlet)))
-
-    for fname,h in zip(filename,hdrlet):
-        print("Applying {0} as Primary WCS to {1}".format(h,fname))
-        hlet = Headerlet.fromfile(h, logging=logging, logmode=logmode)
-        hlet.apply_as_primary(fname, attach=attach, archive=archive,
-                          force=force)
-
-
-@with_logging
-def apply_headerlet_as_alternate(filename, hdrlet, attach=True, wcskey=None,
-                                wcsname=None, logging=False, logmode='w'):
-    """
-    Apply headerlet to a science observation as an alternate WCS
-
-    Parameters
-    ----------
-    filename: string or list of strings
-             File name(s) of science observation whose WCS solution will be updated
-    hdrlet: string or list of strings
-             Headerlet file(s), must match 1-to-1 with input filename(s)
-    attach: boolean
-          flag indicating if the headerlet should be attached as a
-          HeaderletHDU to fobj. If True checks that HDRNAME is unique
-          in the fobj and stops if not.
-    wcskey: string
-          Key value (A-Z, except O) for this alternate WCS
-          If None, the next available key will be used
-    wcsname: string
-          Name to be assigned to this alternate WCS
-          WCSNAME is a required keyword in a Headerlet but this allows the
-          user to change it as desired.
-    logging: boolean
-          enable file logging
-    logmode: 'a' or 'w'
-    """
-    if not isinstance(filename, list):
-        filename = [filename]
-    if not isinstance(hdrlet, list):
-        hdrlet = [hdrlet]
-    if len(hdrlet) != len(filename):
-        logger.critical("Filenames must have matching headerlets. "
-                "{0:d} filenames and {1:d} headerlets specified".format(len(filename),len(hdrlet)))
-
-    for fname,h in zip(filename,hdrlet):
-        print('Applying {0} as an alternate WCS to {1}'.format(h,fname))
-        hlet = Headerlet.fromfile(h, logging=logging, logmode=logmode)
-        hlet.apply_as_alternate(fname, attach=attach,
-                            wcsname=wcsname, wcskey=wcskey)
-
-
-@with_logging
-def attach_headerlet(filename, hdrlet, logging=False, logmode='a'):
-    """
-    Attach Headerlet as an HeaderletHDU to a science file
-
-    Parameters
-    ----------
-    filename: HDUList or list of HDULists
-            science file(s) to which the headerlet should be applied
-    hdrlet: string, Headerlet object or list of strings or Headerlet objects
-            string representing a headerlet file(s), must match 1-to-1 input filename(s)
-    logging: boolean
-            enable file logging
-    logmode: 'a' or 'w'
-    """
-    if not isinstance(filename, list):
-        filename = [filename]
-    if not isinstance(hdrlet, list):
-        hdrlet = [hdrlet]
-    if len(hdrlet) != len(filename):
-        logger.critical("Filenames must have matching headerlets. "
-                "{0:d} filenames and {1:d} headerlets specified".format(len(filename),len(hdrlet)))
-
-    for fname,h in zip(filename,hdrlet):
-        print('Attaching {0} as Headerlet extension to {1}'.format(h,fname))
-        hlet = Headerlet.fromfile(h, logging=logging, logmode=logmode)
-        hlet.attach_to_file(fname,archive=True)
-
-
-@with_logging
-def delete_headerlet(filename, hdrname=None, hdrext=None, distname=None,
-                     logging=False, logmode='w'):
-    """
-    Deletes HeaderletHDU(s) with same HDRNAME from science files
-
-    Notes
-    -----
-    One of hdrname, hdrext or distname should be given.
-    If hdrname is given - delete a HeaderletHDU with a name HDRNAME from fobj.
-    If hdrext is given - delete HeaderletHDU in extension.
-    If distname is given - deletes all HeaderletHDUs with a specific distortion model from fobj.
-    Updates wcscorr
-
-    Parameters
-    ----------
-    filename: string, HDUList or list of strings
-            Filename can be specified as a single filename or HDUList, or
-            a list of filenames
-            Each input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    hdrname: string or None
-        HeaderletHDU primary header keyword HDRNAME
-    hdrext: int, tuple or None
-        HeaderletHDU FITS extension number
-        tuple has the form ('HDRLET', 1)
-    distname: string or None
-        distortion model as specified in the DISTNAME keyword
-    logging: boolean
-             enable file logging
-    logmode: 'a' or 'w'
-    """
-    if not isinstance(filename, list):
-        filename = [filename]
-
-    for f in filename:
-        print("Deleting Headerlet from ",f)
-        _delete_single_headerlet(f, hdrname=hdrname, hdrext=hdrext,
-                            distname=distname, logging=logging, logmode='a')
-
-def _delete_single_headerlet(filename, hdrname=None, hdrext=None, distname=None,
-                     logging=False, logmode='w'):
-    """
-    Deletes HeaderletHDU(s) from a SINGLE science file
-
-    Notes
-    -----
-    One of hdrname, hdrext or distname should be given.
-    If hdrname is given - delete a HeaderletHDU with a name HDRNAME from fobj.
-    If hdrext is given - delete HeaderletHDU in extension.
-    If distname is given - deletes all HeaderletHDUs with a specific distortion model from fobj.
-    Updates wcscorr
-
-    Parameters
-    ----------
-    filename: string or HDUList
-           Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    hdrname: string or None
-        HeaderletHDU primary header keyword HDRNAME
-    hdrext: int, tuple or None
-        HeaderletHDU FITS extension number
-        tuple has the form ('HDRLET', 1)
-    distname: string or None
-        distortion model as specified in the DISTNAME keyword
-    logging: boolean
-             enable file logging
-    logmode: 'a' or 'w'
-    """
-    hdrlet_ind = find_headerlet_HDUs(filename, hdrname=hdrname, hdrext=hdrext,
-                            distname=distname, logging=logging, logmode='a')
-    if len(hdrlet_ind) == 0:
-        message = """
-        No HDUs deleted... No Headerlet HDUs found with '
-        hdrname = %s
-        hdrext  = %s
-        distname = %s
-        Please review input parameters and try again.
-        """ % (hdrname, str(hdrext), distname)
-        logger.critical(message)
-        return
-
-    fobj, fname, close_fobj = parse_filename(filename, mode='update')
-
-    # delete row(s) from WCSCORR table now...
-    #
-    #
-    if hdrname not in ['', ' ', None, 'INDEF']:
-        selections = {'hdrname': hdrname}
-    elif hdrname in ['', ' ', None, 'INDEF'] and hdrext is not None:
-        selections = {'hdrname': fobj[hdrext].header['hdrname']}
-    else:
-        selections = {'distname': distname}
-    wcscorr.delete_wcscorr_row(fobj['WCSCORR'].data, selections)
-
-    # delete the headerlet extension now
-    for hdrind in hdrlet_ind:
-        del fobj[hdrind]
-
-    utils.updateNEXTENDKw(fobj)
-    # Update file object with changes
-    fobj.flush()
-    # close file, if was opened by this function
-    if close_fobj:
-        fobj.close()
-    logger.critical('Deleted headerlet from extension(s) %s ' % str(hdrlet_ind))
-
-
-def headerlet_summary(filename, columns=None, pad=2, maxwidth=None,
-                      output=None, clobber=True, quiet=False):
-    """
-
-    Print a summary of all HeaderletHDUs in a science file to STDOUT, and
-    optionally to a text file
-    The summary includes:
-    HDRLET_ext_number  HDRNAME  WCSNAME DISTNAME SIPNAME NPOLFILE D2IMFILE
-
-    Parameters
-    ----------
-    filename: string or HDUList
-            Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    columns: list
-            List of headerlet PRIMARY header keywords to report in summary
-            By default (set to None), it will use the default set of keywords
-            defined as the global list DEFAULT_SUMMARY_COLS
-    pad: int
-            Number of padding spaces to put between printed columns
-            [Default: 2]
-    maxwidth: int
-            Maximum column width(not counting padding) for any column in summary
-            By default (set to None), each column's full width will be used
-    output: string (optional)
-            Name of optional output file to record summary. This filename
-            can contain environment variables.
-            [Default: None]
-    clobber: bool
-            If True, will overwrite any previous output file of same name
-    quiet: bool
-            If True, will NOT report info to STDOUT
-
-    """
-    if columns is None:
-        summary_cols = DEFAULT_SUMMARY_COLS
-    else:
-        summary_cols = columns
-
-    summary_dict = {}
-    for kw in summary_cols:
-        summary_dict[kw] = copy.deepcopy(COLUMN_DICT)
-
-    # Define Extension number column
-    extnums_col = copy.deepcopy(COLUMN_DICT)
-    extnums_col['name'] = 'EXTN'
-    extnums_col['width'] = 6
-
-    fobj, fname, close_fobj = parse_filename(filename)
-    # find all HDRLET extensions and combine info into a single summary
-    for extn in fobj:
-        if 'extname' in extn.header and extn.header['extname'] == 'HDRLET':
-            hdrlet_indx = fobj.index_of(('hdrlet', extn.header['extver']))
-            try:
-                ext_cols, ext_summary = extn.headerlet.summary(columns=summary_cols)
-                extnums_col['vals'].append(hdrlet_indx)
-                for kw in summary_cols:
-                    for key in COLUMN_DICT:
-                        summary_dict[kw][key].extend(ext_summary[kw][key])
-            except:
-                print("Skipping headerlet")
-                print("Could not read Headerlet from extension ", hdrlet_indx)
-
-    if close_fobj:
-        fobj.close()
-
-    # Print out the summary dictionary
-    print_summary(summary_cols, summary_dict, pad=pad, maxwidth=maxwidth,
-                    idcol=extnums_col, output=output,
-                    clobber=clobber, quiet=quiet)
-
-
-@with_logging
-def restore_from_headerlet(filename, hdrname=None, hdrext=None, archive=True,
-                           force=False, logging=False, logmode='w'):
-    """
-    Restores a headerlet as a primary WCS
-
-    Parameters
-    ----------
-    filename: string or HDUList
-           Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    hdrname: string
-        HDRNAME keyword of HeaderletHDU
-    hdrext: int or tuple
-        Headerlet extension number of tuple ('HDRLET',2)
-    archive: boolean (default: True)
-        When the distortion model in the headerlet is the same as the distortion model of
-        the science file, this flag indicates if the primary WCS should be saved as an alternate
-        nd a headerlet extension.
-        When the distortion models do not match this flag indicates if the current primary and
-        alternate WCSs should be archived as headerlet extensions and alternate WCS.
-    force: boolean (default:False)
-        When the distortion models of the headerlet and the primary do not match, and archive
-        is False, this flag forces an update of the primary.
-    logging: boolean
-           enable file logging
-    logmode: 'a' or 'w'
-    """
-
-    hdrlet_ind = find_headerlet_HDUs(filename, hdrext=hdrext, hdrname=hdrname)
-
-    fobj, fname, close_fobj = parse_filename(filename, mode='update')
-
-    if len(hdrlet_ind) > 1:
-        if hdrext:
-            kwerr = 'hdrext'
-            kwval = hdrext
-        else:
-            kwerr = 'hdrname'
-            kwval = hdrname
-        message = """
-        Multiple Headerlet extensions found with the same name.
-        %d Headerlets with "%s" = %s found in %s.
-        """% (len(hdrlet_ind), kwerr, kwval, fname)
-        if close_fobj:
-            fobj.close()
-        logger.critical(message)
-        raise ValueError
-
-    hdrlet_indx = hdrlet_ind[0]
-
-    # read headerlet from HeaderletHDU into memory
-    if hasattr(fobj[hdrlet_ind[0]], 'hdulist'):
-        hdrlet = fobj[hdrlet_indx].hdulist
-    else:
-        hdrlet = fobj[hdrlet_indx].headerlet # older convention in PyFITS
-
-    # read in the names of the extensions which HeaderletHDU updates
-    extlist = []
-    for ext in hdrlet:
-        if 'extname' in ext.header and ext.header['extname'] == 'SIPWCS':
-            # convert from string to tuple or int
-            sciext = eval(ext.header['sciext'])
-            extlist.append(fobj[sciext])
-    # determine whether distortion is the same
-    current_distname = hdrlet[0].header['distname']
-    same_dist = True
-    if current_distname != fobj[0].header['distname']:
-        same_dist = False
-        if not archive and not force:
-            if close_fobj:
-                fobj.close()
-            message = """
-            Headerlet does not have the same distortion as image!
-            Set "archive"=True to save old distortion model, or
-            set "force"=True to overwrite old model with new.
-            """
-            logger.critical(message)
-            raise ValueError
-
-    # check whether primary WCS has been archived already
-    # Use information from first 'SCI' extension
-    priwcs_name = None
-
-    scihdr = extlist[0].header
-    sci_wcsnames = altwcs.wcsnames(scihdr).values()
-    if 'hdrname' in scihdr:
-        priwcs_hdrname = scihdr['hdrname']
-    else:
-        if 'wcsname' in scihdr:
-            priwcs_hdrname = priwcs_name = scihdr['wcsname']
-        else:
-            if 'idctab' in scihdr:
-                priwcs_hdrname = ''.join(['IDC_',
-                        utils.extract_rootname(scihdr['idctab'], suffix='_idc')])
-            else:
-                priwcs_hdrname = 'UNKNOWN'
-            priwcs_name = priwcs_hdrname
-            scihdr['WCSNAME'] = priwcs_name
-
-    priwcs_unique = verify_hdrname_is_unique(fobj, priwcs_hdrname)
-    if archive and priwcs_unique:
-        if priwcs_unique:
-            newhdrlet = create_headerlet(fobj, sciext=scihdr['extname'],
-                        hdrname=priwcs_hdrname)
-            newhdrlet.attach_to_file(fobj)
-    #
-    # copy hdrlet as a primary
-    #
-    hdrlet.apply_as_primary(fobj, attach=False, archive=archive, force=force)
-
-    utils.updateNEXTENDKw(fobj)
-    fobj.flush()
-    if close_fobj:
-        fobj.close()
-
-
-@with_logging
-def restore_all_with_distname(filename, distname, primary, archive=True,
-                              sciext='SCI', logging=False, logmode='w'):
-    """
-    Restores all HeaderletHDUs with a given distortion model as alternate WCSs and a primary
-
-    Parameters
-    --------------
-    filename: string or HDUList
-           Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    distname: string
-        distortion model as represented by a DISTNAME keyword
-    primary: int or string or None
-        HeaderletHDU to be restored as primary
-        if int - a fits extension
-        if string - HDRNAME
-        if None - use first HeaderletHDU
-    archive: boolean (default True)
-        flag indicating if HeaderletHDUs should be created from the
-        primary and alternate WCSs in fname before restoring all matching
-        headerlet extensions
-    logging: boolean
-         enable file logging
-    logmode: 'a' or 'w'
-    """
-
-    fobj, fname, close_fobj = parse_filename(filename, mode='update')
-
-    hdrlet_ind = find_headerlet_HDUs(fobj, distname=distname)
-    if len(hdrlet_ind) == 0:
-        message = """
-        No Headerlet extensions found with
-
-        DISTNAME = %s in %s.
-
-        For a full list of DISTNAMEs found in all headerlet extensions:
-
-        get_headerlet_kw_names(fobj, kw='DISTNAME')
-        """ % (distname, fname)
-        if close_fobj:
-            fobj.close()
-        logger.critical(message)
-        raise ValueError
-
-    # Interpret 'primary' parameter input into extension number
-    if primary is None:
-        primary_ind = hdrlet_ind[0]
-    elif isinstance(primary, int):
-        primary_ind = primary
-    else:
-        primary_ind = None
-        for ind in hdrlet_ind:
-            if fobj[ind].header['hdrname'] == primary:
-                primary_ind = ind
-                break
-        if primary_ind is None:
-            if close_fobj:
-                fobj.close()
-            message = """
-            No Headerlet extensions found with DISTNAME = %s in %s.
-            """ % (primary, fname)
-            logger.critical(message)
-            raise ValueError
-    # Check to see whether 'primary' HeaderletHDU has same distname as user
-    # specified on input
-
-    # read headerlet from HeaderletHDU into memory
-    if hasattr(fobj[primary_ind], 'hdulist'):
-        primary_hdrlet = fobj[primary_ind].hdulist
-    else:
-        primary_hdrlet = fobj[primary_ind].headerlet # older convention in PyFITS
-    pri_distname = primary_hdrlet[0].header['distname']
-    if pri_distname != distname:
-        if close_fobj:
-            fobj.close()
-        message = """
-        Headerlet extension to be used as PRIMARY WCS
-        has "DISTNAME" = %s
-        "DISTNAME" = %s was specified on input.
-        All updated WCSs must have same DISTNAME. Quitting...'
-        """ % (pri_distname, distname)
-        logger.critical(message)
-        raise ValueError
-
-    # read in the names of the WCSs which the HeaderletHDUs will update
-    wnames = altwcs.wcsnames(fobj[sciext, 1].header)
-
-    # work out how many HeaderletHDUs will be used to update the WCSs
-    numhlt = len(hdrlet_ind)
-    hdrnames = get_headerlet_kw_names(fobj, kw='wcsname')
-
-    # read in headerletHDUs and update WCS keywords
-    for hlet in hdrlet_ind:
-        if fobj[hlet].header['distname'] == distname:
-            if hasattr(fobj[hlet], 'hdulist'):
-                hdrlet = fobj[hlet].hdulist
-            else:
-                hdrlet = fobj[hlet].headerlet # older convention in PyFITS
-            if hlet == primary_ind:
-                hdrlet.apply_as_primary(fobj, attach=False,
-                                        archive=archive, force=True)
-            else:
-                hdrlet.apply_as_alternate(fobj, attach=False,
-                                          wcsname=hdrlet[0].header['wcsname'])
-
-    utils.updateNEXTENDKw(fobj)
-    fobj.flush()
-    if close_fobj:
-        fobj.close()
-
-
-@with_logging
-def archive_as_headerlet(filename, hdrname, sciext='SCI',
-                        wcsname=None, wcskey=None, destim=None,
-                        sipname=None, npolfile=None, d2imfile=None,
-                        author=None, descrip=None, history=None,
-                        nmatch=None, catalog=None,
-                        logging=False, logmode='w'):
-    """
-    Save a WCS as a headerlet extension and write it out to a file.
-
-    This function will create a headerlet, attach it as an extension to the
-    science image (if it has not already been archived) then, optionally,
-    write out the headerlet to a separate headerlet file.
-
-    Either wcsname or wcskey must be provided, if both are given, they must match a valid WCS
-    Updates wcscorr if necessary.
-
-    Parameters
-    ----------
-    filename: string or HDUList
-           Either a filename or PyFITS HDUList object for the input science file
-            An input filename (str) will be expanded as necessary to interpret
-            any environmental variables included in the filename.
-    hdrname: string
-        Unique name for this headerlet, stored as HDRNAME keyword
-    sciext: string
-        name (EXTNAME) of extension that contains WCS to be saved
-    wcsname: string
-        name of WCS to be archived, if " ": stop
-    wcskey: one of A...Z or " " or "PRIMARY"
-        if " " or "PRIMARY" - archive the primary WCS
-    destim: string
-        DESTIM keyword
-        if  NOne, use ROOTNAME or science file name
-    sipname: string or None (default)
-             Name of unique file where the polynomial distortion coefficients were
-             read from. If None, the behavior is:
-             The code looks for a keyword 'SIPNAME' in the science header
-             If not found, for HST it defaults to 'IDCTAB'
-             If there is no SIP model the value is 'NOMODEL'
-             If there is a SIP model but no SIPNAME, it is set to 'UNKNOWN'
-    npolfile: string or None (default)
-             Name of a unique file where the non-polynomial distortion was stored.
-             If None:
-             The code looks for 'NPOLFILE' in science header.
-             If 'NPOLFILE' was not found and there is no npol model, it is set to 'NOMODEL'
-             If npol model exists, it is set to 'UNKNOWN'
-    d2imfile: string
-             Name of a unique file where the detector to image correction was
-             stored. If None:
-             The code looks for 'D2IMFILE' in the science header.
-             If 'D2IMFILE' is not found and there is no d2im correction,
-             it is set to 'NOMODEL'
-             If d2im correction exists, but 'D2IMFILE' is missing from science
-             header, it is set to 'UNKNOWN'
-    author: string
-            Name of user who created the headerlet, added as 'AUTHOR' keyword
-            to headerlet PRIMARY header
-    descrip: string
-            Short description of the solution provided by the headerlet
-            This description will be added as the single 'DESCRIP' keyword
-            to the headerlet PRIMARY header
-    history: filename, string or list of strings
-            Long (possibly multi-line) description of the solution provided
-            by the headerlet. These comments will be added as 'HISTORY' cards
-            to the headerlet PRIMARY header
-            If filename is specified, it will format and attach all text from
-            that file as the history.
-    logging: boolean
-            enable file folling
-    logmode: 'w' or 'a'
-             log file open mode
-    """
-
-    fobj, fname, close_fobj = parse_filename(filename, mode='update')
-
-    if wcsname in [None, ' ', '', 'INDEF'] and wcskey is None:
-        message = """
-        No valid WCS found found in %s.
-        A valid value for either "wcsname" or "wcskey"
-        needs to be specified.
-        """ % fname
-        if close_fobj:
-            fobj.close()
-        logger.critical(message)
-        raise ValueError
-
-    # Translate 'wcskey' value for PRIMARY WCS to valid altwcs value of ' '
-    if wcskey == 'PRIMARY':
-        wcskey = ' '
-    wcskey = wcskey.upper()
-
-    numhlt = countExtn(fobj, 'HDRLET')
-
-    if wcsname is None:
-        scihdr = fobj[sciext, 1].header
-        wcsname = scihdr['wcsname'+wcskey]
-
-    if hdrname in [None, ' ', '']:
-        hdrname = wcsname
-
-    # Check to see whether or not a HeaderletHDU with this hdrname already
-    # exists
-    hdrnames = get_headerlet_kw_names(fobj)
-    if hdrname not in hdrnames:
-        hdrletobj = create_headerlet(fobj, sciext=sciext,
-                                    wcsname=wcsname, wcskey=wcskey,
-                                    hdrname=hdrname,
-                                    sipname=sipname, npolfile=npolfile,
-                                    d2imfile=d2imfile, author=author,
-                                    descrip=descrip, history=history,
-                                    nmatch=nmatch, catalog=catalog,
-                                    logging=False)
-        hlt_hdu = HeaderletHDU.fromheaderlet(hdrletobj)
-
-        if destim is not None:
-            hlt_hdu[0].header['destim'] = destim
-
-        fobj.append(hlt_hdu)
-
-        utils.updateNEXTENDKw(fobj)
-        fobj.flush()
-    else:
-        message = """
-        Headerlet with hdrname %s already archived for WCS %s
-        No new headerlet appended to %s .
-        """ % (hdrname, wcsname, fname)
-        logger.critical(message)
-
-    if close_fobj:
-        fobj.close()
-
-#### Headerlet Class definitions
-class Headerlet(fits.HDUList):
-    """
-    A Headerlet class
-    Ref: http://mediawiki.stsci.edu/mediawiki/index.php/Telescopedia:Headerlets
-    """
-
-    def __init__(self, hdus=[], file=None, logging=False, logmode='w'):
-        """
-        Parameters
-        ----------
-        hdus : list
-                List of HDUs to be used to create the headerlet object itself
-        file:  string
-                File-like object from which HDUs should be read
-        logging: boolean
-                 enable file logging
-        logmode: 'w' or 'a'
-                for internal use only, indicates whether the log file
-                should be open in attach or write mode
-        """
-        self.logging = logging
-        init_logging('class Headerlet', level=logging, mode=logmode)
-
-        super(Headerlet, self).__init__(hdus, file=file)
-
-    def init_attrs(self):
-        self.fname = self.filename()
-        self.hdrname = self[0].header["HDRNAME"]
-        self.wcsname = self[0].header["WCSNAME"]
-        self.upwcsver = self[0].header.get("UPWCSVER", "")
-        self.pywcsver = self[0].header.get("PYWCSVER", "")
-        self.destim = self[0].header["DESTIM"]
-        self.sipname = self[0].header["SIPNAME"]
-        self.idctab = self[0].header["IDCTAB"]
-        self.npolfile = self[0].header["NPOLFILE"]
-        self.d2imfile = self[0].header["D2IMFILE"]
-        self.distname = self[0].header["DISTNAME"]
-
-        try:
-            self.vafactor = self[("SIPWCS", 1)].header.get("VAFACTOR", 1) #None instead of 1?
-        except (IndexError, KeyError):
-            self.vafactor = self[0].header.get("VAFACTOR", 1) #None instead of 1?
-        self.author = self[0].header["AUTHOR"]
-        self.descrip = self[0].header["DESCRIP"]
-
-        self.fit_kws = ['HDRNAME', 'NMATCH', 'CATALOG']
-        self.history = ''
-        # header['HISTORY'] returns an iterable of all HISTORY values
-        if 'HISTORY' in self[0].header:
-            for hist in self[0].header['HISTORY']:
-                self.history += hist + '\n'
-
-        self.d2imerr = 0
-        self.axiscorr = 1
-
-    # Overridden to support the Headerlet logging features
-    @classmethod
-    def fromfile(cls, fileobj, mode='readonly', memmap=False,
-                 save_backup=False, logging=False, logmode='w', **kwargs):
-        hlet = super(cls, cls).fromfile(fileobj, mode, memmap, save_backup,
-                                        **kwargs)
-        if len(hlet) > 0:
-            hlet.init_attrs()
-        hlet.logging = logging
-        init_logging('class Headerlet', level=logging, mode=logmode)
-        return hlet
-
-    @classmethod
-    def fromstring(cls, data, **kwargs):
-        hlet = super(cls, cls).fromstring(data, **kwargs)
-        hlet.logging = logging
-        init_logging('class Headerlet', level=logging, mode=logmode)
-        return hlet
-
-    def  apply_as_primary(self, fobj, attach=True, archive=True, force=False):
-        """
-        Copy this headerlet as a primary WCS to fobj
-
-        Parameters
-        ----------
-        fobj: string, HDUList
-              science file to which the headerlet should be applied
-        attach: boolean
-              flag indicating if the headerlet should be attached as a
-              HeaderletHDU to fobj. If True checks that HDRNAME is unique
-              in the fobj and stops if not.
-        archive: boolean (default is True)
-              When the distortion model in the headerlet is the same as the
-              distortion model of the science file, this flag indicates if
-              the primary WCS should be saved as an alternate and a headerlet
-              extension.
-              When the distortion models do not match this flag indicates if
-              the current primary and alternate WCSs should be archived as
-              headerlet extensions and alternate WCS.
-        force: boolean (default is False)
-              When the distortion models of the headerlet and the primary do
-              not match, and archive is False this flag forces an update
-              of the primary
-        """
-        self.hverify()
-        fobj, fname, close_dest = parse_filename(fobj, mode='update')
-        if not self.verify_dest(fobj, fname):
-            if close_dest:
-                fobj.close()
-            raise ValueError("Destination name does not match headerlet"
-                "Observation %s cannot  be updated with headerlet %s" % (fname, self.hdrname))
-
-        # Check to see whether the distortion model in the destination
-        # matches the distortion model in the headerlet being applied
-
-        dname = self.get_destination_model(fobj)
-        dist_models_equal = self.equal_distmodel(dname)
-        if not dist_models_equal and not force:
-            raise ValueError("Distortion models do not match"
-            " To overwrite the distortion model, set force=True")
-
-        orig_hlt_hdu = None
-        numhlt = countExtn(fobj, 'HDRLET')
-        hdrlet_extnames = get_headerlet_kw_names(fobj)
-
-        # Insure that WCSCORR table has been created with all original
-        # WCS's recorded prior to adding the headerlet WCS
-        wcscorr.init_wcscorr(fobj)
-
-
-        ### start archive
-        # If archive has been specified
-        #   regardless of whether or not the distortion models are equal...
-
-        numsip = countExtn(self, 'SIPWCS')
-        sciext_list = []
-        alt_hlethdu = []
-        for i in range(1, numsip+1):
-            sipheader = self[('SIPWCS', i)].header
-            sciext_list.append((sipheader['TG_ENAME'], sipheader['TG_EVER']))
-        target_ext = sciext_list[0]
-        if archive:
-            if 'wcsname' in fobj[target_ext].header:
-                hdrname = fobj[target_ext].header['WCSNAME']
-                wcsname = hdrname
-            else:
-                hdrname = fobj[0].header['ROOTNAME'] + '_orig'
-                wcsname = None
-            if hdrname not in hdrlet_extnames:
-                # -  if WCS has not been saved, write out WCS as headerlet extension
-                # Create a headerlet for the original Primary WCS data in the file,
-                # create an HDU from the original headerlet, and append it to
-                # the file
-                orig_hlt = create_headerlet(fobj, sciext=sciext_list, #[target_ext],
-                                wcsname=wcsname,
-                                hdrname=hdrname,
-                                logging=self.logging)
-                orig_hlt_hdu = HeaderletHDU.fromheaderlet(orig_hlt)
-                numhlt += 1
-                orig_hlt_hdu.header['EXTVER'] = numhlt
-                logger.info("Created headerlet %s to be attached to file" % hdrname)
-            else:
-                logger.info("Headerlet with name %s is already attached" % hdrname)
-
-
-            if dist_models_equal:
-                # Use the WCSNAME to determine whether or not to archive
-                # Primary WCS as altwcs
-                # wcsname = hwcs.wcs.name
-                scihdr = fobj[target_ext].header
-                if 'hdrname' in scihdr:
-                    priwcs_name = scihdr['hdrname']
-                else:
-                    if 'wcsname' in scihdr:
-                        priwcs_name = scihdr['wcsname']
-                    else:
-                        if 'idctab' in scihdr:
-                            priwcs_name = ''.join(['IDC_',
-                                utils.extract_rootname(scihdr['idctab'],
-                                                        suffix='_idc')])
-                        else:
-                            priwcs_name = 'UNKNOWN'
-                nextkey = altwcs.next_wcskey(fobj, ext=target_ext)
-                altwcs.archiveWCS(fobj, ext=sciext_list, wcskey=nextkey,
-                                  wcsname=priwcs_name)
-            else:
-
-                for hname in altwcs.wcsnames(fobj, ext=target_ext).values():
-                    if hname != 'OPUS' and hname not in hdrlet_extnames:
-                        # get HeaderletHDU for alternate WCS as well
-                        alt_hlet = create_headerlet(fobj, sciext=sciext_list,
-                                wcsname=hname, wcskey=wcskey,
-                                hdrname=hname, sipname=None,
-                                npolfile=None, d2imfile=None,
-                                author=None, descrip=None, history=None,
-                                logging=self.logging)
-                        numhlt += 1
-                        alt_hlet_hdu = HeaderletHDU.fromheaderlet(alt_hlet)
-                        alt_hlet_hdu.header['EXTVER'] = numhlt
-                        alt_hlethdu.append(alt_hlet_hdu)
-                        hdrlet_extnames.append(hname)
-
-        self._del_dest_WCS_ext(fobj)
-        for i in range(1, numsip+1):
-            target_ext = sciext_list[i-1]
-            self._del_dest_WCS(fobj, target_ext)
-            sipwcs = HSTWCS(self, ('SIPWCS', i))
-            idckw = sipwcs._idc2hdr()
-            priwcs = sipwcs.to_fits(relax=True)
-            numnpol = 1
-            numd2im = 1
-            if sipwcs.wcs.has_cd():
-                priwcs[0].header = altwcs.pc2cd(priwcs[0].header)
-            priwcs[0].header.extend(idckw)
-            if 'crder1' in sipheader:
-                for card in sipheader['crder*'].cards:
-                    priwcs[0].header.set(card.keyword, card.value, card.comment,
-                                         after='WCSNAME')
-            # Update WCS with HDRNAME as well
-
-            for kw in ['SIMPLE', 'BITPIX', 'NAXIS', 'EXTEND']:
-                try:
-                    priwcs[0].header.remove(kw)
-                except ValueError:
-                    pass
-
-            priwcs[0].header.set('WCSNAME', self[0].header['WCSNAME'], "")
-            priwcs[0].header.set('WCSAXES', self[('SIPWCS', i)].header['WCSAXES'], "")
-            priwcs[0].header.set('HDRNAME', self[0].header['HDRNAME'], "")
-            if sipwcs.det2im1 or sipwcs.det2im2:
-                try:
-                    d2imerr = self[('SIPWCS', i)].header['D2IMERR*']
-                    priwcs[0].header.extend(d2imerr)
-                except KeyError:
-                    pass
-                try:
-                    priwcs[0].header.append(self[('SIPWCS', i)].header.cards['D2IMEXT'])
-                except KeyError:
-                    pass
-                if 'D2IM1.EXTVER' in priwcs[0].header:
-                    priwcs[0].header['D2IM1.EXTVER'] = self[('SIPWCS', i)].header['D2IM1.EXTVER']
-                    priwcs[('D2IMARR', 1)].header['EXTVER'] = self[('SIPWCS', i)].header['D2IM1.EXTVER']
-                if 'D2IM2.EXTVER' in priwcs[0].header:
-                    priwcs[0].header['D2IM2.EXTVER'] = self[('SIPWCS', i)].header['D2IM2.EXTVER']
-                    priwcs[('D2IMARR', 2)].header['EXTVER'] = self[('SIPWCS', i)].header['D2IM2.EXTVER']
-                    # D2IM1 will NOT exist for WFPC2 data...
-                    if 'D2IM1.EXTVER' in priwcs[0].header:
-                        # only set number of D2IM extensions to 2 if D2IM1 exists
-                        numd2im = 2
-
-            if sipwcs.cpdis1 or sipwcs.cpdis2:
-                try:
-                    cperr = self[('SIPWCS', i)].header['CPERR*']
-                    priwcs[0].header.extend(cperr)
-                except KeyError:
-                    pass
-                try:
-                    priwcs[0].header.append(self[('SIPWCS', i)].header.cards['NPOLEXT'])
-                except KeyError:
-                    pass
-                if 'DP1.EXTVER' in priwcs[0].header:
-                    priwcs[0].header['DP1.EXTVER'] = self[('SIPWCS', i)].header['DP1.EXTVER']
-                    priwcs[('WCSDVARR', 1)].header['EXTVER'] = self[('SIPWCS', i)].header['DP1.EXTVER']
-                if 'DP2.EXTVER' in priwcs[0].header:
-                    priwcs[0].header['DP2.EXTVER'] = self[('SIPWCS', i)].header['DP2.EXTVER']
-                    priwcs[('WCSDVARR', 2)].header['EXTVER'] = self[('SIPWCS', i)].header['DP2.EXTVER']
-                    numnpol = 2
-
-            fobj[target_ext].header.extend(priwcs[0].header)
-            if sipwcs.cpdis1:
-                whdu = priwcs[('WCSDVARR', (i-1)*numnpol+1)].copy()
-                whdu.update_ext_version(self[('SIPWCS', i)].header['DP1.EXTVER'])
-                fobj.append(whdu)
-            if sipwcs.cpdis2:
-                whdu = priwcs[('WCSDVARR', i*numnpol)].copy()
-                whdu.update_ext_version(self[('SIPWCS', i)].header['DP2.EXTVER'])
-                fobj.append(whdu)
-            if sipwcs.det2im1: #or sipwcs.det2im2:
-                whdu = priwcs[('D2IMARR', (i-1)*numd2im+1)].copy()
-                whdu.update_ext_version(self[('SIPWCS', i)].header['D2IM1.EXTVER'])
-                fobj.append(whdu)
-            if sipwcs.det2im2:
-                whdu = priwcs[('D2IMARR', i*numd2im)].copy()
-                whdu.update_ext_version(self[('SIPWCS', i)].header['D2IM2.EXTVER'])
-                fobj.append(whdu)
-
-        update_versions(self[0].header, fobj[0].header)
-        refs = update_ref_files(self[0].header, fobj[0].header)
-        # Update the WCSCORR table with new rows from the headerlet's WCSs
-        wcscorr.update_wcscorr(fobj, self, 'SIPWCS')
-
-        # Append the original headerlet
-        if archive and orig_hlt_hdu:
-            fobj.append(orig_hlt_hdu)
-        # Append any alternate WCS Headerlets
-        if len(alt_hlethdu) > 0:
-            for ahdu in alt_hlethdu:
-                fobj.append(ahdu)
-        if attach:
-            # Finally, append an HDU for this headerlet
-            self.attach_to_file(fobj)
-            utils.updateNEXTENDKw(fobj)
-        if close_dest:
-            fobj.close()
-
-
-    def apply_as_alternate(self, fobj, attach=True, wcskey=None, wcsname=None):
-        """
-        Copy this headerlet as an alternate WCS to fobj
-
-        Parameters
-        ----------
-        fobj: string, HDUList
-              science file/HDUList to which the headerlet should be applied
-        attach: boolean
-              flag indicating if the headerlet should be attached as a
-              HeaderletHDU to fobj. If True checks that HDRNAME is unique
-              in the fobj and stops if not.
-        wcskey: string
-              Key value (A-Z, except O) for this alternate WCS
-              If None, the next available key will be used
-        wcsname: string
-              Name to be assigned to this alternate WCS
-              WCSNAME is a required keyword in a Headerlet but this allows the
-              user to change it as desired.
-
-        """
-        self.hverify()
-        fobj, fname, close_dest = parse_filename(fobj, mode='update')
-        if not self.verify_dest(fobj, fname):
-            if close_dest:
-                fobj.close()
-            raise ValueError("Destination name does not match headerlet"
-                "Observation %s cannot  be updated with headerlet %s" % (fname, self.hdrname))
-
-        # Verify whether this headerlet has the same distortion
-        #found in the image being updated
-        dname = self.get_destination_model(fobj)
-        dist_models_equal = self.equal_distmodel(dname)
-        if not dist_models_equal:
-            raise ValueError("Distortion models do not match \n"
-                             "Headerlet: %s \n"
-                             "Destination file: %s\n"
-            "attach_to_file() can be used to append this headerlet" %(self.distname, dname))
-
-        # Insure that WCSCORR table has been created with all original
-        # WCS's recorded prior to adding the headerlet WCS
-        wcscorr.init_wcscorr(fobj)
-
-        # determine value of WCSNAME to be used
-        if wcsname is not None:
-            wname = wcsname
-        else:
-            wname = self[0].header['WCSNAME']
-        tg_ename = self[('SIPWCS', 1)].header['TG_ENAME']
-        tg_ever = self[('SIPWCS', 1)].header['TG_EVER']
-        # determine what alternate WCS this headerlet will be assigned to
-        if wcskey is None:
-            wkey = altwcs.next_wcskey(fobj[(tg_ename, tg_ever)].header)
-        else:
-            wcskey = wcskey.upper()
-            available_keys = altwcs.available_wcskeys(fobj[(tg_ename, tg_ever)].header)
-            if wcskey in available_keys:
-                wkey = wcskey
-            else:
-                mess = "Observation %s already contains alternate WCS with key %s" % (fname, wcskey)
-                logger.critical(mess)
-                if close_dest:
-                    fobj.close()
-                raise ValueError(mess)
-        numsip = countExtn(self, 'SIPWCS')
-        for idx in range(1, numsip + 1):
-            siphdr = self[('SIPWCS', idx)].header
-            tg_ext = (siphdr['TG_ENAME'], siphdr['TG_EVER'])
-
-            fhdr = fobj[tg_ext].header
-            hwcs = pywcs.WCS(siphdr, self)
-            hwcs_header = hwcs.to_header(key=wkey)
-            _idc2hdr(siphdr, fhdr, towkey=wkey)
-            if hwcs.wcs.has_cd():
-                hwcs_header = altwcs.pc2cd(hwcs_header, key=wkey)
-
-            fhdr.extend(hwcs_header)
-            fhdr['WCSNAME' + wkey] = wname
-            # also update with HDRNAME (a non-WCS-standard kw)
-            for kw in self.fit_kws:
-                #fhdr.insert(wind, pyfits.Card(kw + wkey,
-                #                              self[0].header[kw]))
-                fhdr.append(fits.Card(kw + wkey, self[0].header[kw]))
-        # Update the WCSCORR table with new rows from the headerlet's WCSs
-        wcscorr.update_wcscorr(fobj, self, 'SIPWCS')
-
-        if attach:
-            self.attach_to_file(fobj)
-            utils.updateNEXTENDKw(fobj)
-
-        if close_dest:
-            fobj.close()
-
-    def attach_to_file(self, fobj, archive=False):
-        """
-        Attach Headerlet as an HeaderletHDU to a science file
-
-        Parameters
-        ----------
-        fobj: string, HDUList
-              science file/HDUList to which the headerlet should be applied
-        archive: string
-              Specifies whether or not to update WCSCORR table when attaching
-
-        Notes
-        -----
-        The algorithm used by this method:
-        - verify headerlet can be applied to this file (based on DESTIM)
-        - verify that HDRNAME is unique for this file
-        - attach as HeaderletHDU to fobj
-
-        """
-        self.hverify()
-        fobj, fname, close_dest = parse_filename(fobj, mode='update')
-        destver = self.verify_dest(fobj, fname)
-        hdrver = self.verify_hdrname(fobj)
-        if destver and hdrver:
-
-            numhlt = countExtn(fobj, 'HDRLET')
-            new_hlt = HeaderletHDU.fromheaderlet(self)
-            new_hlt.header['extver'] = numhlt + 1
-            fobj.append(new_hlt)
-            utils.updateNEXTENDKw(fobj)
-        else:
-            message = "Headerlet %s cannot be attached to" % (self.hdrname)
-            message += "observation %s" % (fname)
-            if not destver:
-                message += " * Image %s keyword ROOTNAME not equal to " % (fname)
-                message += " DESTIM = '%s'\n" % (self.destim)
-            if not hdrver:
-                message += " * Image %s already has headerlet " % (fname)
-                message += "with HDRNAME='%s'\n" % (self.hdrname)
-            logger.critical(message)
-        if close_dest:
-            fobj.close()
-
-    def info(self, columns=None, pad=2, maxwidth=None,
-                output=None, clobber=True, quiet=False):
-        """
-        Prints a summary of this headerlet
-        The summary includes:
-        HDRNAME  WCSNAME DISTNAME SIPNAME NPOLFILE D2IMFILE
-
-        Parameters
-        ----------
-        columns: list
-                List of headerlet PRIMARY header keywords to report in summary
-                By default (set to None), it will use the default set of keywords
-                defined as the global list DEFAULT_SUMMARY_COLS
-        pad: int
-                Number of padding spaces to put between printed columns
-                [Default: 2]
-        maxwidth: int
-                Maximum column width(not counting padding) for any column in summary
-                By default (set to None), each column's full width will be used
-        output: string (optional)
-                Name of optional output file to record summary. This filename
-                can contain environment variables.
-                [Default: None]
-        clobber: bool
-                If True, will overwrite any previous output file of same name
-        quiet: bool
-                If True, will NOT report info to STDOUT
-
-        """
-        summary_cols, summary_dict = self.summary(columns=columns)
-        print_summary(summary_cols, summary_dict, pad=pad, maxwidth=maxwidth,
-                        idcol=None, output=output, clobber=clobber, quiet=quiet)
-
-    def summary(self, columns=None):
-        """
-        Returns a summary of this headerlet as a dictionary
-
-        The summary includes a summary of the distortion model as :
-            HDRNAME  WCSNAME DISTNAME SIPNAME NPOLFILE D2IMFILE
-
-        Parameters
-        ----------
-        columns: list
-            List of headerlet PRIMARY header keywords to report in summary
-            By default(set to None), it will use the default set of keywords
-            defined as the global list DEFAULT_SUMMARY_COLS
-
-        Returns
-        -------
-        summary: dict
-            Dictionary of values for summary
-        """
-        if columns is None:
-            summary_cols = DEFAULT_SUMMARY_COLS
-        else:
-            summary_cols = columns
-
-        # Initialize summary dict based on requested columns
-        summary = {}
-        for kw in summary_cols:
-            summary[kw] = copy.deepcopy(COLUMN_DICT)
-
-        # Populate the summary with headerlet values
-        for kw in summary_cols:
-            if kw in self[0].header:
-                val = self[0].header[kw]
-            else:
-                val = 'INDEF'
-            summary[kw]['vals'].append(val)
-            summary[kw]['width'].append(max(len(val), len(kw)))
-
-        return summary_cols, summary
-
-    def hverify(self):
-        """
-        Verify the headerlet file is a valid fits file and has
-        the required Primary Header keywords
-        """
-        self.verify()
-        header = self[0].header
-        assert('DESTIM' in header and header['DESTIM'].strip())
-        assert('HDRNAME' in header and header['HDRNAME'].strip())
-        assert('UPWCSVER' in header)
-
-    def verify_hdrname(self, dest):
-        """
-        Verifies that the headerlet can be applied to the observation
-
-        Reports whether or not this file already has a headerlet with this
-        HDRNAME.
-        """
-        unique = verify_hdrname_is_unique(dest, self.hdrname)
-        logger.debug("verify_hdrname() returned %s"%unique)
-        return unique
-
-    def get_destination_model(self, dest):
-        """
-        Verifies that the headerlet can be applied to the observation
-
-        Determines whether or not the file specifies the same distortion
-        model/reference files.
-        """
-        destim_opened = False
-        if not isinstance(dest, fits.HDUList):
-            destim = fits.open(dest)
-            destim_opened = True
-        else:
-            destim = dest
-        dname = destim[0].header['DISTNAME'] if 'distname' in destim[0].header \
-              else self.build_distname(dest)
-        if destim_opened:
-            destim.close()
-        return dname
-
-    def equal_distmodel(self, dmodel):
-        if dmodel != self[0].header['DISTNAME']:
-            if self.logging:
-                    message = """
-                    Distortion model in headerlet not the same as destination model
-                    Headerlet model  : %s
-                    Destination model: %s
-                    """ % (self[0].header['DISTNAME'], dmodel)
-                    logger.critical(message)
-            return False
-        else:
-            return True
-
-    def verify_dest(self, dest, fname):
-        """
-        verifies that the headerlet can be applied to the observation
-
-        DESTIM in the primary header of the headerlet must match ROOTNAME
-        of the science file (or the name of the destination file)
-        """
-        try:
-            if not isinstance(dest, fits.HDUList):
-                droot = fits.getval(dest, 'ROOTNAME')
-            else:
-                droot = dest[0].header['ROOTNAME']
-        except KeyError:
-            logger.debug("Keyword 'ROOTNAME' not found in destination file")
-            droot = dest.split('.fits')[0]
-        if droot == self.destim:
-            logger.debug("verify_destim() returned True")
-            return True
-        else:
-            logger.debug("verify_destim() returned False")
-            logger.critical("Destination name does not match headerlet. "
-                    "Observation %s cannot  be updated with headerlet %s" % (fname, self.hdrname))
-            return False
-
-    def build_distname(self, dest):
-        """
-        Builds the DISTNAME for dest based on reference file names.
-        """
-
-        try:
-            npolfile = dest[0].header['NPOLFILE']
-        except KeyError:
-            npolfile = None
-        try:
-            d2imfile = dest[0].header['D2IMFILE']
-        except KeyError:
-            d2imfile = None
-
-        sipname, idctab = utils.build_sipname(dest, dest, None)
-        npolname, npolfile = utils.build_npolname(dest, npolfile)
-        d2imname, d2imfile = utils.build_d2imname(dest, d2imfile)
-        dname = utils.build_distname(sipname,npolname,d2imname)
-        return dname
-
-    def tofile(self, fname, destim=None, hdrname=None, clobber=False):
-        """
-        Write this headerlet to a file
-
-        Parameters
-        ----------
-        fname: string
-               file name
-        destim: string (optional)
-                provide a value for DESTIM keyword
-        hdrname: string (optional)
-                provide a value for HDRNAME keyword
-        clobber: boolean
-                a flag which allows to overwrte an existing file
-        """
-        if not destim or not hdrname:
-            self.hverify()
-        self.writeto(fname, clobber=clobber)
-
-    def _del_dest_WCS(self, dest, ext=None):
-        """
-        Delete the WCS of a science file extension
-        """
-
-        logger.info("Deleting all WCSs of file %s" % dest.filename())
-        numext = len(dest)
-
-        if ext:
-            fext = dest[ext]
-            self._remove_d2im(fext)
-            self._remove_sip(fext)
-            self._remove_lut(fext)
-            self._remove_primary_WCS(fext)
-            self._remove_idc_coeffs(fext)
-            self._remove_fit_values(fext)
-        else:
-            for idx in range(numext):
-                # Only delete WCS from extensions which may have WCS keywords
-                if ('XTENSION' in dest[idx].header and
-                    dest[idx].header['XTENSION'] == 'IMAGE'):
-                    self._remove_d2im(dest[idx])
-                    self._remove_sip(dest[idx])
-                    self._remove_lut(dest[idx])
-                    self._remove_primary_WCS(dest[idx])
-                    self._remove_idc_coeffs(dest[idx])
-                    self._remove_fit_values(dest[idx])
-        self._remove_ref_files(dest[0])
-        """
-        if not ext:
-            self._remove_alt_WCS(dest, ext=range(numext))
-        else:
-           self._remove_alt_WCS(dest, ext=ext)
-        """
-    def _del_dest_WCS_ext(self, dest):
-        numwdvarr = countExtn(dest, 'WCSDVARR')
-        numd2im = countExtn(dest, 'D2IMARR')
-        if numwdvarr > 0:
-            for idx in range(1, numwdvarr + 1):
-                del dest[('WCSDVARR', idx)]
-        if numd2im > 0:
-            for idx in range(1, numd2im + 1):
-                del dest[('D2IMARR', idx)]
-
-    def _remove_ref_files(self, phdu):
-        """
-        phdu: Primary HDU
-        """
-        refkw = ['IDCTAB', 'NPOLFILE', 'D2IMFILE', 'SIPNAME', 'DISTNAME']
-        for kw in refkw:
-            try:
-                del phdu.header[kw]
-            except KeyError:
-                pass
-
-    def _remove_fit_values(self, ext):
-        """
-        Remove the any existing astrometric fit values from a FITS extension
-        """
-
-        logger.debug("Removing astrometric fit values from (%s, %s)"%
-                     (ext.name, ext.ver))
-        dkeys = altwcs.wcskeys(ext.header)
-        if 'O' in dkeys: dkeys.remove('O') # Do not remove wcskey='O' values
-        for fitkw in ['NMATCH', 'CATALOG']:
-            for k in dkeys:
-                fkw = (fitkw+k).rstrip()
-                if fkw in ext.header:
-                    del ext.header[fkw]
-
-    def _remove_sip(self, ext):
-        """
-        Remove the SIP distortion of a FITS extension
-        """
-
-        logger.debug("Removing SIP distortion from (%s, %s)"
-                     % (ext.name, ext.ver))
-        for prefix in ['A', 'B', 'AP', 'BP']:
-            try:
-                order = ext.header[prefix + '_ORDER']
-                del ext.header[prefix + '_ORDER']
-            except KeyError:
-                continue
-            for i in range(order + 1):
-                for j in range(order + 1):
-                    key = prefix + '_%d_%d' % (i, j)
-                    try:
-                        del ext.header[key]
-                    except KeyError:
-                        pass
-        try:
-            del ext.header['IDCTAB']
-        except KeyError:
-            pass
-
-    def _remove_lut(self, ext):
-        """
-        Remove the Lookup Table distortion of a FITS extension
-        """
-
-        logger.debug("Removing LUT distortion from (%s, %s)"
-                     % (ext.name, ext.ver))
-        try:
-            cpdis = ext.header['CPDIS*']
-        except KeyError:
-            return
-        try:
-            for c in range(1, len(cpdis) + 1):
-                del ext.header['DP%s*...' % c]
-                del ext.header[cpdis.cards[c - 1].keyword]
-            del ext.header['CPERR*']
-            del ext.header['NPOLFILE']
-            del ext.header['NPOLEXT']
-        except KeyError:
-            pass
-
-    def _remove_d2im(self, ext):
-        """
-        Remove the Detector to Image correction of a FITS extension
-        """
-
-        logger.debug("Removing D2IM correction from (%s, %s)"
-                     % (ext.name, ext.ver))
-        try:
-            d2imdis = ext.header['D2IMDIS*']
-        except KeyError:
-            return
-        try:
-            for c in range(1, len(d2imdis) + 1):
-                del ext.header['D2IM%s*...' % c]
-                del ext.header[d2imdis.cards[c - 1].keyword]
-            del ext.header['D2IMERR*']
-            del ext.header['D2IMFILE']
-            del ext.header['D2IMEXT']
-        except KeyError:
-            pass
-
-    def _remove_alt_WCS(self, dest, ext):
-        """
-        Remove Alternate WCSs of a FITS extension.
-        A WCS with wcskey 'O' is never deleted.
-        """
-        dkeys = altwcs.wcskeys(dest[('SCI', 1)].header)
-        for val in ['O', '', ' ']:
-            if val in dkeys:
-                dkeys.remove(val) # Never delete WCS with wcskey='O'
-
-        logger.debug("Removing alternate WCSs with keys %s from %s"
-                     % (dkeys, dest.filename()))
-        for k in dkeys:
-            altwcs.deleteWCS(dest, ext=ext, wcskey=k)
-
-    def _remove_primary_WCS(self, ext):
-        """
-        Remove the primary WCS of a FITS extension
-        """
-
-        logger.debug("Removing Primary WCS from (%s, %s)"
-                     % (ext.name, ext.ver))
-        naxis = ext.header['NAXIS']
-        for key in basic_wcs:
-            for i in range(1, naxis + 1):
-                try:
-                    del ext.header[key + str(i)]
-                except KeyError:
-                    pass
-        try:
-            del ext.header['WCSAXES']
-        except KeyError:
-            pass
-        try:
-            del ext.header['WCSNAME']
-        except KeyError:
-            pass
-
-    def _remove_idc_coeffs(self, ext):
-        """
-        Remove IDC coefficients of a FITS extension
-        """
-
-        logger.debug("Removing IDC coefficient from (%s, %s)"
-                     % (ext.name, ext.ver))
-        coeffs = ['OCX10', 'OCX11', 'OCY10', 'OCY11', 'IDCSCALE']
-        for k in coeffs:
-            try:
-                del ext.header[k]
-            except KeyError:
-                pass
-
-@with_logging
-def _idc2hdr(fromhdr, tohdr, towkey=' '):
-    """
-    Copy the IDC (HST specific) keywords from one header to another
-
-    """
-    # save some of the idc coefficients
-    coeffs = ['OCX10', 'OCX11', 'OCY10', 'OCY11', 'IDCSCALE']
-    for c in coeffs:
-        try:
-            tohdr[c+towkey] = fromhdr[c]
-            logger.debug("Copied %s to header")
-        except KeyError:
-            continue
-
-
-def get_extname_extver_list(fobj, sciext):
-    """
-    Create a list of (EXTNAME, EXTVER) tuples
-
-    Based on sciext keyword (see docstring for create_headerlet)
-    walk throughh the file and convert extensions in `sciext` to
-    valid (EXTNAME, EXTVER) tuples.
-    """
-    extlist = []
-    if isinstance(sciext, int):
-        if sciext == 0:
-            extname = 'PRIMARY'
-            extver = 1
-        else:
-            try:
-                extname = fobj[sciext].header['EXTNAME']
-            except KeyError:
-                extname = ""
-            try:
-                extver = fobj[sciext].header['EXTVER']
-            except KeyError:
-                extver = 1
-        extlist.append((extname, extver))
-    elif isinstance(sciext, str):
-        if sciext == 'PRIMARY':
-            extname = "PRIMARY"
-            extver = 1
-            extlist.append((extname, extver))
-        else:
-            for ext in fobj:
-                try:
-                    extname = ext.header['EXTNAME']
-                except KeyError:
-                    continue
-                if extname.upper() == sciext.upper():
-                    try:
-                        extver = ext.header['EXTVER']
-                    except KeyError:
-                        extver = 1
-                    extlist.append((extname, extver))
-    elif isinstance(sciext, list):
-        if isinstance(sciext[0], int):
-            for i in sciext:
-                try:
-                    extname = fobj[i].header['EXTNAME']
-                except KeyError:
-                    if i == 0:
-                        extname = "PRIMARY"
-                        extver = 1
-                    else:
-                        extname = ""
-                try:
-                    extver = fobj[i].header['EXTVER']
-                except KeyError:
-                    extver = 1
-                extlist.append((extname, extver))
-        else:
-            extlist = sciext[:]
-    else:
-        errstr = "Expected sciext to be a list of FITS extensions with science data\n"+\
-              "    a valid EXTNAME string, or an integer."
-        logger.critical(errstr)
-        raise ValueError
-    return extlist
-
-
-class HeaderletHDU(fits.hdu.nonstandard.FitsHDU):
-    """
-    A non-standard extension HDU for encapsulating Headerlets in a file.  These
-    HDUs have an extension type of HDRLET and their EXTNAME is derived from the
-    Headerlet's HDRNAME.
-
-    The data itself is a FITS file embedded within the HDU data.  The file name
-    is derived from the HDRNAME keyword, and should be in the form
-    `<HDRNAME>_hdr.fits`.  If the COMPRESS keyword evaluates to `True`, the tar
-    file is compressed with gzip compression.
-
-    The structure of this HDU is the same as that proposed for the 'FITS'
-    extension type proposed here:
-    http://listmgr.cv.nrao.edu/pipermail/fitsbits/2002-April/thread.html
-
-    The Headerlet contained in the HDU's data can be accessed by the
-    `headerlet` attribute.
-    """
-
-    _extension = 'HDRLET'
-
-    @lazyproperty
-    def headerlet(self):
-        """Return the encapsulated headerlet as a Headerlet object.
-
-        This is similar to the hdulist property inherited from the FitsHDU
-        class, though the hdulist property returns a normal HDUList object.
-        """
-
-        return Headerlet(self.hdulist)
-
-    @classmethod
-    def fromheaderlet(cls, headerlet, compress=False):
-        """
-        Creates a new HeaderletHDU from a given Headerlet object.
-
-        Parameters
-        ----------
-        headerlet : `Headerlet`
-            A valid Headerlet object.
-
-        compress : bool, optional
-            Gzip compress the headerlet data.
-
-        Returns
-        -------
-        hlet : `HeaderletHDU`
-            A `HeaderletHDU` object for the given `Headerlet` that can be
-            attached as an extension to an existing `HDUList`.
-        """
-
-        # TODO: Perhaps check that the given object is in fact a valid
-        # Headerlet
-        hlet = cls.fromhdulist(headerlet, compress)
-
-        # Add some more headerlet-specific keywords to the header
-        phdu = headerlet[0]
-
-        if 'SIPNAME' in phdu.header:
-            sipname = phdu.header['SIPNAME']
-        else:
-            sipname = phdu.header['WCSNAME']
-
-        hlet.header['HDRNAME'] = (phdu.header['HDRNAME'],
-                                  phdu.header.comments['HDRNAME'])
-        hlet.header['DATE'] = (phdu.header['DATE'],
-                               phdu.header.comments['DATE'])
-        hlet.header['SIPNAME'] = (sipname, 'SIP distortion model name')
-        hlet.header['WCSNAME'] = (phdu.header['WCSNAME'], 'WCS name')
-        hlet.header['DISTNAME'] = (phdu.header['DISTNAME'],
-                                   'Distortion model name')
-        hlet.header['NPOLFILE'] = (phdu.header['NPOLFILE'],
-                                   phdu.header.comments['NPOLFILE'])
-        hlet.header['D2IMFILE'] = (phdu.header['D2IMFILE'],
-                                   phdu.header.comments['D2IMFILE'])
-        hlet.header['EXTNAME'] = (cls._extension, 'Extension name')
-
-        return hlet
-
-
-fits.register_hdu(HeaderletHDU)
diff --git a/lib/stwcs/wcsutil/hstwcs.py b/lib/stwcs/wcsutil/hstwcs.py
deleted file mode 100644
index bfebcfc..0000000
--- a/lib/stwcs/wcsutil/hstwcs.py
+++ /dev/null
@@ -1,988 +0,0 @@
-from __future__ import absolute_import, division, print_function # confidence high
-
-import os
-from astropy.wcs import WCS
-from astropy.io import fits
-from stwcs.distortion import models, coeff_converter
-import numpy as np
-from stsci.tools import fileutil
-
-from . import altwcs
-from . import getinput
-from . import mappings
-from . import instruments
-from .mappings import inst_mappings, ins_spec_kw
-from .mappings import basic_wcs
-
-__docformat__ = 'restructuredtext'
-
-#
-#### Utility functions copied from 'updatewcs.utils' to avoid circular imports
-#
-def extract_rootname(kwvalue,suffix=""):
-    """ Returns the rootname from a full reference filename
-
-        If a non-valid value (any of ['','N/A','NONE','INDEF',None]) is input,
-            simply return a string value of 'NONE'
-
-        This function will also replace any 'suffix' specified with a blank.
-    """
-    # check to see whether a valid kwvalue has been provided as input
-    if kwvalue.strip() in ['','N/A','NONE','INDEF',None]:
-        return 'NONE' # no valid value, so return 'NONE'
-
-    # for a valid kwvalue, parse out the rootname
-    # strip off any environment variable from input filename, if any are given
-    if '$' in kwvalue:
-        fullval = kwvalue[kwvalue.find('$')+1:]
-    else:
-        fullval = kwvalue
-    # Extract filename without path from kwvalue
-    fname = os.path.basename(fullval).strip()
-
-    # Now, rip out just the rootname from the full filename
-    rootname = fileutil.buildNewRootname(fname)
-
-    # Now, remove any known suffix from rootname
-    rootname = rootname.replace(suffix,'')
-    return rootname.strip()
-
-def build_default_wcsname(idctab):
-
-    idcname = extract_rootname(idctab,suffix='_idc')
-    wcsname = 'IDC_' + idcname
-    return wcsname
-
-
-class NoConvergence(Exception):
-    """
-    An error class used to report non-convergence and/or divergence of
-    numerical methods. It is used to report errors in the iterative solution
-    used by the :py:meth:`~stwcs.hstwcs.HSTWCS.all_world2pix`\ .
-
-    Attributes
-    ----------
-
-    best_solution : numpy.array
-        Best solution achieved by the method.
-
-    accuracy : float
-        Accuracy of the :py:attr:`best_solution`\ .
-
-    niter : int
-        Number of iterations performed by the numerical method to compute
-        :py:attr:`best_solution`\ .
-
-    divergent : None, numpy.array
-        Indices of the points in :py:attr:`best_solution` array for which the
-        solution appears to be divergent. If the solution does not diverge,
-        `divergent` will be set to `None`.
-
-    failed2converge : None, numpy.array
-        Indices of the points in :py:attr:`best_solution` array for which the
-        solution failed to converge within the specified maximum number
-        of iterations. If there are no non-converging poits (i.e., if
-        the required accuracy has been achieved for all points) then
-        `failed2converge` will be set to `None`.
-
-    """
-    def __init__(self, *args, **kwargs):
-        super(NoConvergence, self).__init__(*args)
-
-        self.best_solution  = kwargs.pop('best_solution', None)
-        self.accuracy       = kwargs.pop('accuracy', None)
-        self.niter          = kwargs.pop('niter', None)
-        self.divergent      = kwargs.pop('divergent', None)
-        self.failed2converge= kwargs.pop('failed2converge', None)
-
-
-#
-#### HSTWCS Class definition
-#
-class HSTWCS(WCS):
-
-    def __init__(self, fobj=None, ext=None, minerr=0.0, wcskey=" "):
-        """
-        Create a WCS object based on the instrument.
-
-        In addition to basic WCS keywords this class provides
-        instrument specific information needed in distortion computation.
-
-        Parameters
-        ----------
-        fobj : str or `astropy.io.fits.HDUList` object or None
-            file name, e.g j9irw4b1q_flt.fits
-            fully qualified filename[EXTNAME,EXTNUM], e.g. j9irw4b1q_flt.fits[sci,1]
-            `astropy.io.fits` file object, e.g fits.open('j9irw4b1q_flt.fits'), in which case the
-            user is responsible for closing the file object.
-        ext : int, tuple or None
-            extension number
-            if ext is tuple, it must be ("EXTNAME", EXTNUM), e.g. ("SCI", 2)
-            if ext is None, it is assumed the data is in the primary hdu
-        minerr : float
-            minimum value a distortion correction must have in order to be applied.
-            If CPERRja, CQERRja are smaller than minerr, the corersponding
-            distortion is not applied.
-        wcskey : str
-            A one character A-Z or " " used to retrieve and define an
-            alternate WCS description.
-        """
-
-        self.inst_kw = ins_spec_kw
-        self.minerr = minerr
-        self.wcskey = wcskey
-
-        if fobj is not None:
-            filename, hdr0, ehdr, phdu = getinput.parseSingleInput(f=fobj,
-                                                                   ext=ext)
-            self.filename = filename
-            instrument_name = hdr0.get('INSTRUME', 'DEFAULT')
-            if instrument_name == 'DEFAULT' or instrument_name not in list(inst_mappings.keys()):
-                #['IRAF/ARTDATA','',' ','N/A']:
-                self.instrument = 'DEFAULT'
-            else:
-                self.instrument = instrument_name
-            # Set the correct reference frame
-            refframe = determine_refframe(hdr0)
-            ehdr['RADESYS'] = refframe
-
-            WCS.__init__(self, ehdr, fobj=phdu, minerr=self.minerr,
-                         key=self.wcskey)
-            if self.instrument == 'DEFAULT':
-                self.pc2cd()
-            # If input was a `astropy.io.fits.HDUList` object, it's the user's
-            # responsibility to close it, otherwise, it's closed here.
-            if not isinstance(fobj, fits.HDUList):
-                phdu.close()
-            self.setInstrSpecKw(hdr0, ehdr)
-            self.readIDCCoeffs(ehdr)
-            extname = ehdr.get('EXTNAME', '')
-            extnum = ehdr.get('EXTVER', None)
-            self.extname = (extname, extnum)
-        else:
-            # create a default HSTWCS object
-            self.instrument = 'DEFAULT'
-            WCS.__init__(self, minerr=self.minerr, key=self.wcskey)
-            self.pc2cd()
-            self.setInstrSpecKw()
-        self.setPscale()
-        self.setOrient()
-
-    @property
-    def naxis1(self):
-        return self._naxis1
-
-    @naxis1.setter
-    def naxis1(self, value):
-        self._naxis1 = value
-
-    @property
-    def naxis2(self):
-        return self._naxis2
-
-    @naxis2.setter
-    def naxis2(self, value):
-        self._naxis2 = value
-
-    def readIDCCoeffs(self, header):
-        """
-        Reads in first order IDCTAB coefficients if present in the header
-        """
-        coeffs = ['ocx10', 'ocx11', 'ocy10', 'ocy11', 'idcscale',
-                    'idcv2ref','idcv3ref', 'idctheta']
-        for c in coeffs:
-            self.__setattr__(c, header.get(c, None))
-
-    def setInstrSpecKw(self, prim_hdr=None, ext_hdr=None):
-        """
-        Populate the instrument specific attributes:
-
-        These can be in different headers but each instrument class has knowledge
-        of where to look for them.
-
-        Parameters
-        ----------
-        prim_hdr : `astropy.io.fits.Header`
-            primary header
-        ext_hdr : `astropy.io.fits.Header`
-            extension header
-
-        """
-        if self.instrument in list(inst_mappings.keys()):
-            inst_kl = inst_mappings[self.instrument]
-            inst_kl = instruments.__dict__[inst_kl]
-            insobj = inst_kl(prim_hdr, ext_hdr)
-
-            for key in self.inst_kw:
-                try:
-                    self.__setattr__(key, insobj.__getattribute__(key))
-                except AttributeError:
-                    # Some of the instrument's attributes are recorded in the primary header and
-                    # were already set, (e.g. 'DETECTOR'), the code below is a check for that case.
-                    if not self.__getattribute__(key):
-                        raise
-                    else:
-                        pass
-
-        else:
-            raise KeyError("Unsupported instrument - %s" %self.instrument)
-
-    def setPscale(self):
-        """
-        Calculates the plate scale from the CD matrix
-        """
-        try:
-            cd11 = self.wcs.cd[0][0]
-            cd21 = self.wcs.cd[1][0]
-            self.pscale = np.sqrt(np.power(cd11,2)+np.power(cd21,2)) * 3600.
-        except AttributeError:
-            if self.wcs.has_cd():
-                print("This file has a PC matrix. You may want to convert it \n \
-                to a CD matrix, if reasonable, by running pc2.cd() method.\n \
-                The plate scale can be set then by calling setPscale() method.\n")
-            self.pscale = None
-
-    def setOrient(self):
-        """
-        Computes ORIENTAT from the CD matrix
-        """
-        try:
-            cd12 = self.wcs.cd[0][1]
-            cd22 = self.wcs.cd[1][1]
-            self.orientat = np.rad2deg(np.arctan2(cd12,cd22))
-        except AttributeError:
-            if self.wcs.has_cd():
-                print("This file has a PC matrix. You may want to convert it \n \
-                to a CD matrix, if reasonable, by running pc2.cd() method.\n \
-                The orientation can be set then by calling setOrient() method.\n")
-            self.pscale = None
-
-    def updatePscale(self, scale):
-        """
-        Updates the CD matrix with a new plate scale
-        """
-        self.wcs.cd = self.wcs.cd/self.pscale*scale
-        self.setPscale()
-
-    def readModel(self, update=False, header=None):
-        """
-        Reads distortion model from IDCTAB.
-
-        If IDCTAB is not found ('N/A', "", or not found on disk), then
-        if SIP coefficients and first order IDCTAB coefficients are present
-        in the header, restore the idcmodel from the header.
-        If not - assign None to self.idcmodel.
-
-        Parameters
-        ----------
-        header : `astropy.io.fits.Header`
-            fits extension header
-        update : bool (False)
-            if True - record the following IDCTAB quantities as header keywords:
-            CX10, CX11, CY10, CY11, IDCSCALE, IDCTHETA, IDCXREF, IDCYREF,
-            IDCV2REF, IDCV3REF
-        """
-        if self.idctab in [None, '', ' ','N/A']:
-            #Keyword idctab is not present in header - check for sip coefficients
-            if header is not None and 'IDCSCALE' in header:
-                self._readModelFromHeader(header)
-            else:
-                print("Distortion model is not available: IDCTAB=None\n")
-                self.idcmodel = None
-        elif not os.path.exists(fileutil.osfn(self.idctab)):
-            if header is not None and 'IDCSCALE' in header:
-                self._readModelFromHeader(header)
-            else:
-                print('Distortion model is not available: IDCTAB file %s not found\n' % self.idctab)
-                self.idcmodel = None
-        else:
-            self.readModelFromIDCTAB(header=header, update=update)
-
-    def _readModelFromHeader(self, header):
-        # Recreate idc model from SIP coefficients and header kw
-        print('Restoring IDC model from SIP coefficients\n')
-        model = models.GeometryModel()
-        cx, cy = coeff_converter.sip2idc(self)
-        model.cx = cx
-        model.cy = cy
-        model.name = "sip"
-        model.norder = header['A_ORDER']
-
-        refpix = {}
-        refpix['XREF'] = header['IDCXREF']
-        refpix['YREF'] = header['IDCYREF']
-        refpix['PSCALE'] = header['IDCSCALE']
-        refpix['V2REF'] = header['IDCV2REF']
-        refpix['V3REF'] = header['IDCV3REF']
-        refpix['THETA'] = header['IDCTHETA']
-        model.refpix = refpix
-
-        self.idcmodel = model
-
-
-    def readModelFromIDCTAB(self, header=None, update=False):
-        """
-        Read distortion model from idc table.
-
-        Parameters
-        ----------
-        header : `astropy.io.fits.Header`
-            fits extension header
-        update : booln (False)
-            if True - save teh following as header keywords:
-            CX10, CX11, CY10, CY11, IDCSCALE, IDCTHETA, IDCXREF, IDCYREF,
-            IDCV2REF, IDCV3REF
-
-        """
-        if self.date_obs == None:
-            print('date_obs not available\n')
-            self.idcmodel = None
-            return
-        if self.filter1 == None and self.filter2 == None:
-            'No filter information available\n'
-            self.idcmodel = None
-            return
-
-        self.idcmodel = models.IDCModel(self.idctab,
-                    chip=self.chip, direction='forward', date=self.date_obs,
-                    filter1=self.filter1, filter2=self.filter2,
-                    offtab=self.offtab, binned=self.binned)
-
-        if self.ltv1 != 0. or self.ltv2 != 0.:
-            self.resetLTV()
-
-        if update:
-            if header==None:
-                print('Update header with IDC model kw requested but header was not provided\n.')
-            else:
-                self._updatehdr(header)
-
-    def resetLTV(self):
-        """
-        Reset LTV values for polarizer data
-
-        The polarizer field is smaller than the detector field.
-        The distortion coefficients are defined for the entire
-        polarizer field and the LTV values are set as with subarray
-        data. This may also be true for other special filters.
-        This is a special case when the observation is considered
-        a subarray in terms of detector field but a full frame in
-        terms of distortion model.
-        To avoid shifting the distortion coefficients the LTV values
-        are reset to 0.
-        """
-        if self.naxis1 == self.idcmodel.refpix['XSIZE'] and  \
-           self.naxis2 == self.idcmodel.refpix['YSIZE']:
-            self.ltv1 = 0.
-            self.ltv2 = 0.
-
-    def wcs2header(self, sip2hdr=False, idc2hdr=True, wcskey=None, relax=False):
-        """
-        Create a `astropy.io.fits.Header` object from WCS keywords.
-
-        If the original header had a CD matrix, return a CD matrix,
-        otherwise return a PC matrix.
-
-        Parameters
-        ----------
-        sip2hdr : bool
-            If True - include SIP coefficients
-        """
-
-        h = self.to_header(key=wcskey, relax=relax)
-        if not wcskey:
-            wcskey = self.wcs.alt
-        if self.wcs.has_cd():
-            h = altwcs.pc2cd(h, key=wcskey)
-
-        if 'wcsname' not in h:
-            if self.idctab is not None:
-                wname = build_default_wcsname(self.idctab)
-            else:
-                wname = 'DEFAULT'
-            h['wcsname{0}'.format(wcskey)] = wname
-
-        if idc2hdr:
-            for card in self._idc2hdr():
-                h[card.keyword + wcskey] = (card.value, card.comment)
-        try:
-            del h['RESTFRQ']
-            del h['RESTWAV']
-        except KeyError: pass
-
-        if sip2hdr and self.sip:
-            for card in self._sip2hdr('a'):
-                h[card.keyword] = (card.value, card.comment)
-            for card in self._sip2hdr('b'):
-                h[card.keyword] = (card.value, card.comment)
-
-            try:
-                ap = self.sip.ap
-            except AssertionError:
-                ap = None
-            try:
-                bp = self.sip.bp
-            except AssertionError:
-                bp = None
-
-            if ap:
-                for card in self._sip2hdr('ap'):
-                    h[card.keyword] = (card.value, card.comment)
-            if bp:
-                for card in self._sip2hdr('bp'):
-                    h[card.keyword] = (card.value, card.comment)
-        return h
-
-    def _sip2hdr(self, k):
-        """
-        Get a set of SIP coefficients in the form of an array
-        and turn them into a `astropy.io.fits.Cardlist`.
-        k - one of 'a', 'b', 'ap', 'bp'
-        """
-
-        cards = [] #fits.CardList()
-        korder = self.sip.__getattribute__(k+'_order')
-        cards.append(fits.Card(keyword=k.upper()+'_ORDER', value=korder))
-        coeffs = self.sip.__getattribute__(k)
-        ind = coeffs.nonzero()
-        for i in range(len(ind[0])):
-            card = fits.Card(keyword=k.upper()+'_'+str(ind[0][i])+'_'+str(ind[1][i]),
-                             value=coeffs[ind[0][i], ind[1][i]])
-            cards.append(card)
-        return cards
-
-    def _idc2hdr(self):
-        # save some of the idc coefficients
-        coeffs = ['ocx10', 'ocx11', 'ocy10', 'ocy11', 'idcscale']
-        cards = [] #fits.CardList()
-        for c in coeffs:
-            try:
-                val = self.__getattribute__(c)
-            except AttributeError:
-                continue
-            if val:
-                cards.append(fits.Card(keyword=c, value=val))
-        return cards
-
-    def pc2cd(self):
-        if not self.wcs.has_pc():
-            self.wcs.pc = self.wcs.get_pc()
-        self.wcs.cd = self.wcs.pc * self.wcs.cdelt[1]
-
-    def all_world2pix(self, *args, **kwargs):
-        """
-        all_world2pix(*arg, accuracy=1.0e-4, maxiter=20, adaptive=False, \
-detect_divergence=True, quiet=False)
-
-        Performs full inverse transformation using iterative solution
-        on full forward transformation with complete distortion model.
-
-        Parameters
-        ----------
-        accuracy : float, optional (Default = 1.0e-4)
-            Required accuracy of the solution. Iteration terminates when the
-            correction to the solution found during the previous iteration
-            is smaller (in the sence of the L2 norm) than `accuracy`\ .
-
-        maxiter : int, optional (Default = 20)
-            Maximum number of iterations allowed to reach the solution.
-
-        adaptive : bool, optional (Default = False)
-            Specifies whether to adaptively select only points that did not
-            converge to a solution whithin the required accuracy for the
-            next iteration. Default is recommended for HST as well as most
-            other instruments.
-
-            .. note::
-               The :py:meth:`all_world2pix` uses a vectorized implementation
-               of the method of consecutive approximations (see `Notes`
-               section below) in which it iterates over *all* input poits
-               *regardless* until the required accuracy has been reached for
-               *all* input points. In some cases it may be possible that
-               *almost all* points have reached the required accuracy but
-               there are only a few of input data points left for which
-               additional iterations may be needed (this depends mostly on the
-               characteristics of the geometric distortions for a given
-               instrument). In this situation it may be
-               advantageous to set `adaptive` = `True`\ in which
-               case :py:meth:`all_world2pix` will continue iterating *only* over
-               the points that have not yet converged to the required
-               accuracy. However, for the HST's ACS/WFC detector, which has
-               the strongest distortions of all HST instruments, testing has
-               shown that enabling this option would lead to a about 10-30\%
-               penalty in computational time (depending on specifics of the
-               image, geometric distortions, and number of input points to be
-               converted). Therefore, for HST instruments,
-               it is recommended to set `adaptive` = `False`\ . The only
-               danger in getting this setting wrong will be a performance
-               penalty.
-
-            .. note::
-               When `detect_divergence` is `True`\ , :py:meth:`all_world2pix` \
-               will automatically switch to the adaptive algorithm once
-               divergence has been detected.
-
-        detect_divergence : bool, optional (Default = True)
-            Specifies whether to perform a more detailed analysis of the
-            convergence to a solution. Normally :py:meth:`all_world2pix`
-            may not achieve the required accuracy
-            if either the `tolerance` or `maxiter` arguments are too low.
-            However, it may happen that for some geometric distortions
-            the conditions of convergence for the the method of consecutive
-            approximations used by :py:meth:`all_world2pix` may not be
-            satisfied, in which case consecutive approximations to the
-            solution will diverge regardless of the `tolerance` or `maxiter`
-            settings.
-
-            When `detect_divergence` is `False`\ , these divergent points
-            will be detected as not having achieved the required accuracy
-            (without further details). In addition, if `adaptive` is `False`
-            then the algorithm will not know that the solution (for specific
-            points) is diverging and will continue iterating and trying to
-            "improve" diverging solutions. This may result in NaN or Inf
-            values in the return results (in addition to a performance
-            penalties). Even when `detect_divergence` is
-            `False`\ , :py:meth:`all_world2pix`\ , at the end of the iterative
-            process, will identify invalid results (NaN or Inf) as "diverging"
-            solutions and will raise :py:class:`NoConvergence` unless
-            the `quiet` parameter is set to `True`\ .
-
-            When `detect_divergence` is `True`\ , :py:meth:`all_world2pix` will
-            detect points for
-            which current correction to the coordinates is larger than
-            the correction applied during the previous iteration **if** the
-            requested accuracy **has not yet been achieved**\ . In this case,
-            if `adaptive` is `True`, these points will be excluded from
-            further iterations and if `adaptive`
-            is `False`\ , :py:meth:`all_world2pix` will automatically
-            switch to the adaptive algorithm.
-
-            .. note::
-               When accuracy has been achieved, small increases in
-               current corrections may be possible due to rounding errors
-               (when `adaptive` is `False`\ ) and such increases
-               will be ignored.
-
-            .. note::
-               Setting `detect_divergence` to `True` will incurr about 5-10\%
-               performance penalty (in our testing on ACS/WFC images).
-               Because the benefits of enabling this feature outweigh
-               the small performance penalty, it is recommended to set
-               `detect_divergence` to `True`\ , unless extensive testing
-               of the distortion models for images from specific
-               instruments show a good stability of the numerical method
-               for a wide range of coordinates (even outside the image
-               itself).
-
-            .. note::
-               Indices of the diverging inverse solutions will be reported
-               in the `divergent` attribute of the
-               raised :py:class:`NoConvergence` object.
-
-        quiet : bool, optional (Default = False)
-            Do not throw :py:class:`NoConvergence` exceptions when the method
-            does not converge to a solution with the required accuracy
-            within a specified number of maximum iterations set by `maxiter`
-            parameter. Instead, simply return the found solution.
-
-        Raises
-        ------
-        NoConvergence
-            The method does not converge to a
-            solution with the required accuracy within a specified number
-            of maximum iterations set by the `maxiter` parameter.
-
-        Notes
-        -----
-        Inputs can either be (RA, Dec, origin) or (RADec, origin) where RA
-        and Dec are 1-D arrays/lists of coordinates and RADec is an
-        array/list of pairs of coordinates.
-
-        Using the method of consecutive approximations we iterate starting
-        with the initial approximation, which is computed using the
-        non-distorion-aware :py:meth:`wcs_world2pix` (or equivalent).
-
-        The :py:meth:`all_world2pix` function uses a vectorized implementation
-        of the method of consecutive approximations and therefore it is
-        highly efficient (>30x) when *all* data points that need to be
-        converted from sky coordinates to image coordinates are passed at
-        *once*\ . Therefore, it is advisable, whenever possible, to pass
-        as input a long array of all points that need to be converted
-        to :py:meth:`all_world2pix` instead of calling :py:meth:`all_world2pix`
-        for each data point. Also see the note to the `adaptive` parameter.
-
-        Examples
-        --------
-        >>> import stwcs
-        >>> from astropy.io import fits
-        >>> hdulist = fits.open('j94f05bgq_flt.fits')
-        >>> w = stwcs.wcsutil.HSTWCS(hdulist, ext=('sci',1))
-        >>> hdulist.close()
-
-        >>> ra, dec = w.all_pix2world([1,2,3],[1,1,1],1); print(ra); print(dec)
-        [ 5.52645241  5.52649277  5.52653313]
-        [-72.05171776 -72.05171295 -72.05170814]
-        >>> radec = w.all_pix2world([[1,1],[2,1],[3,1]],1); print(radec)
-        [[  5.52645241 -72.05171776]
-         [  5.52649277 -72.05171295]
-         [  5.52653313 -72.05170814]]
-        >>> x, y = w.all_world2pix(ra,dec,1)
-        >>> print(x)
-        [ 1.00000233  2.00000232  3.00000233]
-        >>> print(y)
-        [ 0.99999997  0.99999997  0.99999998]
-        >>> xy = w.all_world2pix(radec,1)
-        >>> print(xy)
-        [[ 1.00000233  0.99999997]
-         [ 2.00000232  0.99999997]
-         [ 3.00000233  0.99999998]]
-        >>> xy = w.all_world2pix(radec,1, maxiter=3, accuracy=1.0e-10, \
-quiet=False)
-        NoConvergence: 'HSTWCS.all_world2pix' failed to converge to requested \
-accuracy after 3 iterations.
-
-        >>>
-        Now try to use some diverging data:
-        >>> divradec = w.all_pix2world([[1.0,1.0],[10000.0,50000.0],\
-[3.0,1.0]],1); print(divradec)
-        [[  5.52645241 -72.05171776]
-         [  7.15979392 -70.81405561]
-         [  5.52653313 -72.05170814]]
-
-        >>> try:
-        >>>   xy = w.all_world2pix(divradec,1, maxiter=20, accuracy=1.0e-4, \
-adaptive=False, detect_divergence=True, quiet=False)
-        >>> except stwcs.wcsutil.hstwcs.NoConvergence as e:
-        >>>   print("Indices of diverging points: {}".format(e.divergent))
-        >>>   print("Indices of poorly converging points: {}".format(e.failed2converge))
-        >>>   print("Best solution: {}".format(e.best_solution))
-        >>>   print("Achieved accuracy: {}".format(e.accuracy))
-        >>>   raise e
-        Indices of diverging points:
-        [1]
-        Indices of poorly converging points:
-        None
-        Best solution:
-        [[  1.00006219e+00   9.99999288e-01]
-         [ -1.99440907e+06   1.44308548e+06]
-         [  3.00006257e+00   9.99999316e-01]]
-        Achieved accuracy:
-        [[  5.98554253e-05   6.79918148e-07]
-         [  8.59514088e+11   6.61703754e+11]
-         [  6.02334592e-05   6.59713067e-07]]
-        Traceback (innermost last):
-          File "<console>", line 8, in <module>
-        NoConvergence: 'HSTWCS.all_world2pix' failed to converge to the requested accuracy.
-        After 5 iterations, the solution is diverging at least for one input point.
-
-        >>> try:
-        >>>   xy = w.all_world2pix(divradec,1, maxiter=20, accuracy=1.0e-4, \
-adaptive=False, detect_divergence=False, quiet=False)
-        >>> except stwcs.wcsutil.hstwcs.NoConvergence as e:
-        >>>   print("Indices of diverging points: {}".format(e.divergent))
-        >>>   print("Indices of poorly converging points: {}".format(e.failed2converge))
-        >>>   print("Best solution: {}".format(e.best_solution))
-        >>>   print("Achieved accuracy: {}".format(e.accuracy))
-        >>>   raise e
-        Indices of diverging points:
-        [1]
-        Indices of poorly converging points:
-        None
-        Best solution:
-        [[  1.   1.]
-         [ nan  nan]
-         [  3.   1.]]
-        Achieved accuracy:
-        [[  0.   0.]
-         [ nan  nan]
-         [  0.   0.]]
-        Traceback (innermost last):
-          File "<console>", line 8, in <module>
-        NoConvergence: 'HSTWCS.all_world2pix' failed to converge to the requested accuracy.
-        After 20 iterations, the solution is diverging at least for one input point.
-
-        """
-        #####################################################################
-        ##                     PROCESS ARGUMENTS:                          ##
-        #####################################################################
-        nargs = len(args)
-
-        if nargs == 3:
-            try:
-                ra     = np.asarray(args[0], dtype=np.float64)
-                dec    = np.asarray(args[1], dtype=np.float64)
-                #assert( len(ra.shape) == 1 and len(dec.shape) == 1 )
-                origin = int(args[2])
-                vect1D = True
-            except:
-                raise TypeError("When providing three arguments, they must " \
-                            "be (Ra, Dec, origin) where Ra and Dec are " \
-                            "Nx1 vectors.")
-        elif nargs == 2:
-            try:
-                rd  = np.asarray(args[0], dtype=np.float64)
-                #assert( rd.shape[1] == 2 )
-                ra  = rd[:,0]
-                dec = rd[:,1]
-                origin = int(args[1])
-                vect1D = False
-            except:
-                raise TypeError("When providing two arguments, they must " \
-                            "be (RaDec, origin) where RaDec is a Nx2 array.")
-        else:
-            raise TypeError("Expected 2 or 3 arguments, {:d} given." \
-                            .format(nargs))
-
-        # process optional arguments:
-        accuracy          = kwargs.pop('accuracy', 1.0e-4)
-        maxiter           = kwargs.pop('maxiter', 20)
-        adaptive          = kwargs.pop('adaptive', False)
-        detect_divergence = kwargs.pop('detect_divergence', True)
-        quiet             = kwargs.pop('quiet', False)
-
-        #####################################################################
-        ##                INITIALIZE ITERATIVE PROCESS:                    ##
-        #####################################################################
-        x0, y0 = self.wcs_world2pix(ra, dec, origin) # <-- initial approximation
-                                                  #     (WCS based only)
-
-        # see if an iterative solution is required (when any of the
-        # non-CD-matrix corrections are present). If not required
-        # return initial approximation (x0, y0).
-        if self.sip is None and \
-           self.cpdis1 is None and self.cpdis2 is None and \
-           self.det2im1 is None and self.det2im2 is None:
-            # no non-WCS corrections are detected - return
-            # initial approximation
-            if vect1D:
-                return [x0, y0]
-            else:
-                return np.dstack([x0,y0])[0]
-
-        x  = x0.copy() # 0-order solution
-        y  = y0.copy() # 0-order solution
-
-        # initial correction:
-        dx, dy = self.pix2foc(x, y, origin)
-        # If pix2foc does not apply all the required distortion
-        # corrections then replace the above line with:
-        #r0, d0 = self.all_pix2world(x, y, origin)
-        #dx, dy = self.wcs_world2pix(r0, d0, origin )
-        dx -= x0
-        dy -= y0
-
-        # update initial solution:
-        x -= dx
-        y -= dy
-
-        # norn (L2) squared of the correction:
-        dn2prev   = dx**2+dy**2
-        dn2       = dn2prev
-
-        # prepare for iterative process
-        iterlist  = list(range(1, maxiter+1))
-        accuracy2 = accuracy**2
-        ind       = None
-        inddiv    = None
-
-        npts      = x.shape[0]
-
-        # turn off numpy runtime warnings for 'invalid' and 'over':
-        old_invalid = np.geterr()['invalid']
-        old_over    = np.geterr()['over']
-        np.seterr(invalid = 'ignore', over = 'ignore')
-
-        #####################################################################
-        ##                     NON-ADAPTIVE ITERATIONS:                    ##
-        #####################################################################
-        if not adaptive:
-            for k in iterlist:
-                # check convergence:
-                if np.max(dn2) < accuracy2:
-                    break
-
-                # find correction to the previous solution:
-                dx, dy = self.pix2foc(x, y, origin)
-                # If pix2foc does not apply all the required distortion
-                # corrections then replace the above line with:
-                #r0, d0 = self.all_pix2world(x, y, origin)
-                #dx, dy = self.wcs_world2pix(r0, d0, origin )
-                dx -= x0
-                dy -= y0
-
-                # update norn (L2) squared of the correction:
-                dn2 = dx**2+dy**2
-
-                # check for divergence (we do this in two stages
-                # to optimize performance for the most common
-                # scenario when succesive approximations converge):
-                if detect_divergence:
-                    ind, = np.where(dn2 <= dn2prev)
-                    if ind.shape[0] < npts:
-                        inddiv, = np.where(
-                            np.logical_and(dn2 > dn2prev, dn2 >= accuracy2))
-                        if inddiv.shape[0] > 0:
-                            # apply correction only to the converging points:
-                            x[ind] -= dx[ind]
-                            y[ind] -= dy[ind]
-                            # switch to adaptive iterations:
-                            ind, = np.where((dn2 >= accuracy2) & \
-                                        (dn2 <= dn2prev) & np.isfinite(dn2))
-                            iterlist = iterlist[k:]
-                            adaptive = True
-                            break
-                    #dn2prev[ind] = dn2[ind]
-                    dn2prev = dn2
-
-                # apply correction:
-                x -= dx
-                y -= dy
-
-        #####################################################################
-        ##                      ADAPTIVE ITERATIONS:                       ##
-        #####################################################################
-        if adaptive:
-            if ind is None:
-                ind = np.asarray(list(range(npts)), dtype=np.int64)
-
-            for k in iterlist:
-                # check convergence:
-                if ind.shape[0] == 0:
-                    break
-
-                # find correction to the previous solution:
-                dx[ind], dy[ind] = self.pix2foc(x[ind], y[ind], origin)
-                # If pix2foc does not apply all the required distortion
-                # corrections then replace the above line with:
-                #r0[ind], d0[ind] = self.all_pix2world(x[ind], y[ind], origin)
-                #dx[ind], dy[ind] = self.wcs_world2pix(r0[ind], d0[ind], origin)
-                dx[ind] -= x0[ind]
-                dy[ind] -= y0[ind]
-
-                # update norn (L2) squared of the correction:
-                dn2 = dx**2+dy**2
-
-                # update indices of elements that still need correction:
-                if detect_divergence:
-                    ind, = np.where((dn2 >= accuracy2) & (dn2 <= dn2prev))
-                    #ind = ind[np.where((dn2[ind] >= accuracy2) & (dn2[ind] <= dn2prev))]
-                    dn2prev[ind] = dn2[ind]
-                else:
-                    ind, = np.where(dn2 >= accuracy2)
-                    #ind = ind[np.where(dn2[ind] >= accuracy2)]
-
-                # apply correction:
-                x[ind] -= dx[ind]
-                y[ind] -= dy[ind]
-
-        #####################################################################
-        ##         FINAL DETECTION OF INVALID, DIVERGING,                  ##
-        ##         AND FAILED-TO-CONVERGE POINTS                           ##
-        #####################################################################
-        # Identify diverging and/or invalid points:
-        invalid = (((~np.isfinite(y)) | (~np.isfinite(x)) | \
-                    (~np.isfinite(dn2))) & \
-                   (np.isfinite(ra)) &  (np.isfinite(dec)))
-        # When detect_divergence==False, dn2prev is outdated (it is the
-        # norm^2 of the very first correction). Still better than nothing...
-        inddiv, = np.where(((dn2 >= accuracy2) & (dn2 > dn2prev)) | invalid)
-        if inddiv.shape[0] == 0:
-            inddiv = None
-        # identify points that did not converge within
-        # 'maxiter' iterations:
-        if k >= maxiter:
-            ind,= np.where((dn2 >= accuracy2) & (dn2 <= dn2prev) & (~invalid))
-            if ind.shape[0] == 0:
-                ind = None
-        else:
-            ind = None
-
-        #####################################################################
-        ##      RAISE EXCEPTION IF DIVERGING OR TOO SLOWLY CONVERGING      ##
-        ##      DATA POINTS HAVE BEEN DETECTED:                            ##
-        #####################################################################
-        # raise exception if diverging or too slowly converging
-        if (ind is not None or inddiv is not None) and not quiet:
-            if vect1D:
-                sol  = [x, y]
-                err  = [np.abs(dx), np.abs(dy)]
-            else:
-                sol  = np.dstack( [x, y] )[0]
-                err  = np.dstack( [np.abs(dx), np.abs(dy)] )[0]
-
-            # restore previous numpy error settings:
-            np.seterr(invalid = old_invalid, over = old_over)
-
-            if inddiv is None:
-                raise NoConvergence("'HSTWCS.all_world2pix' failed to "        \
-                    "converge to the requested accuracy after {:d} "         \
-                    "iterations.".format(k), best_solution = sol,            \
-                    accuracy = err, niter = k, failed2converge = ind,        \
-                    divergent = None)
-            else:
-                raise NoConvergence("'HSTWCS.all_world2pix' failed to "        \
-                    "converge to the requested accuracy.{0:s}"               \
-                    "After {1:d} iterations, the solution is diverging "     \
-                    "at least for one input point."                          \
-                    .format(os.linesep, k), best_solution = sol,             \
-                    accuracy = err, niter = k, failed2converge = ind,        \
-                    divergent = inddiv)
-
-        #####################################################################
-        ##             FINALIZE AND FORMAT DATA FOR RETURN:                ##
-        #####################################################################
-        # restore previous numpy error settings:
-        np.seterr(invalid = old_invalid, over = old_over)
-
-        if vect1D:
-            return [x, y]
-        else:
-            return np.dstack( [x, y] )[0]
-
-    def _updatehdr(self, ext_hdr):
-        #kw2add : OCX10, OCX11, OCY10, OCY11
-        # record the model in the header for use by pydrizzle
-        ext_hdr['OCX10'] = self.idcmodel.cx[1,0]
-        ext_hdr['OCX11'] = self.idcmodel.cx[1,1]
-        ext_hdr['OCY10'] = self.idcmodel.cy[1,0]
-        ext_hdr['OCY11'] = self.idcmodel.cy[1,1]
-        ext_hdr['IDCSCALE'] = self.idcmodel.refpix['PSCALE']
-        ext_hdr['IDCTHETA'] = self.idcmodel.refpix['THETA']
-        ext_hdr['IDCXREF'] = self.idcmodel.refpix['XREF']
-        ext_hdr['IDCYREF'] = self.idcmodel.refpix['YREF']
-        ext_hdr['IDCV2REF'] =  self.idcmodel.refpix['V2REF']
-        ext_hdr['IDCV3REF'] = self.idcmodel.refpix['V3REF']
-
-    def printwcs(self):
-        """
-        Print the basic WCS keywords.
-        """
-        print('WCS Keywords\n')
-        print('CD_11  CD_12: %r %r' % (self.wcs.cd[0,0],  self.wcs.cd[0,1]))
-        print('CD_21  CD_22: %r %r' % (self.wcs.cd[1,0],  self.wcs.cd[1,1]))
-        print('CRVAL    : %r %r' % (self.wcs.crval[0], self.wcs.crval[1]))
-        print('CRPIX    : %r %r' % (self.wcs.crpix[0], self.wcs.crpix[1]))
-        print('NAXIS    : %d %d' % (self.naxis1, self.naxis2))
-        print('Plate Scale : %r' % self.pscale)
-        print('ORIENTAT : %r' % self.orientat)
-
-
-def determine_refframe(phdr):
-    """
-    Determine the reference frame in standard FITS WCS terms.
-
-    Parameters
-    ----------
-    phdr : `astropy.io.fits.Header`
-        Primary Header of an HST observation
-
-    In HST images the reference frame is recorded in the primary extension as REFFRAME.
-    Values are "GSC1" which means FK5 or ICRS (for GSC2 observations).
-    """
-    try:
-        refframe = phdr['REFFRAME']
-    except KeyError:
-        refframe = " "
-    if refframe == "GSC1":
-        refframe = "FK5"
-    return refframe
diff --git a/lib/stwcs/wcsutil/instruments.py b/lib/stwcs/wcsutil/instruments.py
deleted file mode 100644
index f662513..0000000
--- a/lib/stwcs/wcsutil/instruments.py
+++ /dev/null
@@ -1,320 +0,0 @@
-from __future__ import absolute_import, division, print_function # confidence high
-
-from .mappings import ins_spec_kw
-
-class InstrWCS(object):
-    """
-    A base class for instrument specific keyword definition.
-    It prvides a default implementation (modeled by ACS) for
-    all set_kw methods.
-    """
-    def __init__(self, hdr0=None, hdr=None):
-        self.exthdr = hdr
-        self.primhdr = hdr0
-        self.set_ins_spec_kw()
-
-    def set_ins_spec_kw(self):
-        """
-        This method MUST call all set_kw methods.
-        There should be a set_kw method for all kw listed in
-        mappings.ins_spec_kw. TypeError handles the case when
-        fobj='DEFAULT'.
-        """
-        self.set_idctab()
-        self.set_offtab()
-        self.set_date_obs()
-        self.set_ra_targ()
-        self.set_dec_targ()
-        self.set_pav3()
-        self.set_detector()
-        self.set_filter1()
-        self.set_filter2()
-        self.set_vafactor()
-        self.set_naxis1()
-        self.set_naxis2()
-        self.set_ltv1()
-        self.set_ltv2()
-        self.set_binned()
-        self.set_chip()
-        self.set_parity()
-
-    def set_idctab(self):
-        try:
-            self.idctab = self.primhdr['IDCTAB']
-        except (KeyError, TypeError):
-            self.idctab = None
-
-    def set_offtab(self):
-        try:
-            self.offtab = self.primhdr['OFFTAB']
-        except (KeyError, TypeError):
-            self.offtab = None
-
-    def set_date_obs(self):
-        try:
-            self.date_obs = self.primhdr['DATE-OBS']
-        except (KeyError, TypeError):
-            self.date_obs = None
-
-    def set_ra_targ(self):
-        try:
-            self.ra_targ = self.primhdr['RA-TARG']
-        except (KeyError, TypeError):
-            self.ra_targ = None
-
-    def set_dec_targ(self):
-        try:
-            self.dec_targ = self.primhdr['DEC-TARG']
-        except (KeyError, TypeError):
-            self.dec_targ = None
-
-    def set_pav3(self):
-        try:
-            self.pav3 = self.primhdr['PA_V3']
-        except (KeyError, TypeError):
-            self.pav3 = None
-
-    def set_filter1(self):
-        try:
-            self.filter1 = self.primhdr['FILTER1']
-        except (KeyError, TypeError):
-            self.filter1 = None
-
-    def set_filter2(self):
-        try:
-            self.filter2 = self.primhdr['FILTER2']
-        except (KeyError, TypeError):
-            self.filter2 = None
-
-    def set_vafactor(self):
-        try:
-            self.vafactor = self.exthdr['VAFACTOR']
-        except (KeyError, TypeError):
-            self.vafactor = 1
-
-    def set_naxis1(self):
-        try:
-            self.naxis1 = self.exthdr['naxis1']
-        except (KeyError, TypeError):
-            try:
-                self.naxis1 = self.exthdr['npix1']
-            except (KeyError, TypeError):
-                self.naxis1 = None
-
-    def set_naxis2(self):
-        try:
-            self.naxis2 = self.exthdr['naxis2']
-        except (KeyError, TypeError):
-            try:
-                self.naxis2 = self.exthdr['npix2']
-            except (KeyError, TypeError):
-                self.naxis2 = None
-
-    def set_ltv1(self):
-        try:
-            self.ltv1 = self.exthdr['LTV1']
-        except (KeyError, TypeError):
-            self.ltv1 = 0.0
-
-    def set_ltv2(self):
-        try:
-            self.ltv2 = self.exthdr['LTV2']
-        except (KeyError, TypeError):
-            self.ltv2 = 0.0
-
-    def set_binned(self):
-        try:
-            self.binned = self.exthdr['BINAXIS1']
-        except (KeyError, TypeError):
-            self.binned = 1
-
-    def set_chip(self):
-        try:
-            self.chip = self.exthdr['CCDCHIP']
-        except (KeyError, TypeError):
-            self.chip = 1
-
-    def set_parity(self):
-        self.parity = [[1.0,0.0],[0.0,-1.0]]
-
-    def set_detector(self):
-        # each instrument has a different kw for detector and it can be
-        # in a different header, so this is to be handled by the instrument classes
-        self.detector = 'DEFAULT'
-
-class ACSWCS(InstrWCS):
-    """
-    get instrument specific kw
-    """
-
-    def __init__(self, hdr0, hdr):
-        self.primhdr = hdr0
-        self.exthdr = hdr
-        InstrWCS.__init__(self,hdr0, hdr)
-        self.set_ins_spec_kw()
-
-    def set_detector(self):
-        try:
-            self.detector = self.primhdr['DETECTOR']
-        except KeyError:
-            print('ERROR: Detector kw not found.\n')
-            raise
-
-    def set_parity(self):
-        parity = {'WFC':[[1.0,0.0],[0.0,-1.0]],
-                'HRC':[[-1.0,0.0],[0.0,1.0]],
-                'SBC':[[-1.0,0.0],[0.0,1.0]]}
-
-        if self.detector not in list(parity.keys()):
-            parity = InstrWCS.set_parity(self)
-        else:
-            self.parity = parity[self.detector]
-
-
-class WFPC2WCS(InstrWCS):
-
-
-    def __init__(self, hdr0, hdr):
-        self.primhdr = hdr0
-        self.exthdr = hdr
-        InstrWCS.__init__(self,hdr0, hdr)
-        self.set_ins_spec_kw()
-
-    def set_filter1(self):
-        self.filter1 = self.primhdr.get('FILTNAM1', None)
-        if self.filter1 == " " or self.filter1 == None:
-            self.filter1 = 'CLEAR1'
-
-    def set_filter2(self):
-        self.filter2 = self.primhdr.get('FILTNAM2', None)
-        if self.filter2 == " " or self.filter2 == None:
-            self.filter2 = 'CLEAR2'
-
-
-    def set_binned(self):
-        mode = self.primhdr.get('MODE', 1)
-        if mode == 'FULL':
-            self.binned = 1
-        elif mode == 'AREA':
-            self.binned = 2
-
-    def set_chip(self):
-        self.chip = self.exthdr.get('DETECTOR', 1)
-
-    def set_parity(self):
-        self.parity = [[-1.0,0.],[0.,1.0]]
-
-    def set_detector(self):
-        try:
-            self.detector = self.exthdr['DETECTOR']
-        except KeyError:
-            print('ERROR: Detector kw not found.\n')
-            raise
-
-
-class WFC3WCS(InstrWCS):
-    """
-    Create a WFC3 detector specific class
-    """
-
-    def __init__(self, hdr0, hdr):
-        self.primhdr = hdr0
-        self.exthdr = hdr
-        InstrWCS.__init__(self,hdr0, hdr)
-        self.set_ins_spec_kw()
-
-    def set_detector(self):
-        try:
-            self.detector = self.primhdr['DETECTOR']
-        except KeyError:
-            print('ERROR: Detector kw not found.\n')
-            raise
-
-    def set_filter1(self):
-        self.filter1 = self.primhdr.get('FILTER', None)
-        if self.filter1 == " " or self.filter1 == None:
-            self.filter1 = 'CLEAR'
-
-    def set_filter2(self):
-        #Nicmos idc tables do not allow 2 filters.
-        self.filter2 = 'CLEAR'
-
-    def set_parity(self):
-        parity = {'UVIS':[[-1.0,0.0],[0.0,1.0]],
-          'IR':[[-1.0,0.0],[0.0,1.0]]}
-
-        if self.detector not in list(parity.keys()):
-            parity = InstrWCS.set_parity(self)
-        else:
-            self.parity = parity[self.detector]
-
-class NICMOSWCS(InstrWCS):
-    """
-    Create a NICMOS specific class
-    """
-
-    def __init__(self, hdr0, hdr):
-        self.primhdr = hdr0
-        self.exthdr = hdr
-        InstrWCS.__init__(self,hdr0, hdr)
-        self.set_ins_spec_kw()
-
-    def set_parity(self):
-        self.parity = [[-1.0,0.],[0.,1.0]]
-
-    def set_filter1(self):
-        self.filter1 = self.primhdr.get('FILTER', None)
-        if self.filter1 == " " or self.filter1 == None:
-            self.filter1 = 'CLEAR'
-
-    def set_filter2(self):
-        #Nicmos idc tables do not allow 2 filters.
-        self.filter2 = 'CLEAR'
-
-    def set_chip(self):
-        self.chip = self.detector
-
-    def set_detector(self):
-        try:
-            self.detector = self.primhdr['CAMERA']
-        except KeyError:
-            print('ERROR: Detector kw not found.\n')
-            raise
-
-class STISWCS(InstrWCS):
-    """
-    A STIS specific class
-    """
-
-    def __init__(self, hdr0, hdr):
-        self.primhdr = hdr0
-        self.exthdr = hdr
-        InstrWCS.__init__(self,hdr0, hdr)
-        self.set_ins_spec_kw()
-
-    def set_parity(self):
-        self.parity = [[-1.0,0.],[0.,1.0]]
-
-    def set_filter1(self):
-        self.filter1 = self.exthdr.get('OPT_ELEM', None)
-        if self.filter1 == " " or self.filter1 == None:
-            self.filter1 = 'CLEAR1'
-
-    def set_filter2(self):
-        self.filter2 = self.exthdr.get('FILTER', None)
-        if self.filter2 == " " or self.filter2 == None:
-            self.filter2 = 'CLEAR2'
-
-    def set_detector(self):
-        try:
-            self.detector = self.primhdr['DETECTOR']
-        except KeyError:
-            print('ERROR: Detector kw not found.\n')
-            raise
-
-    def set_date_obs(self):
-        try:
-            self.date_obs = self.exthdr['DATE-OBS']
-        except (KeyError, TypeError):
-            self.date_obs = None
-
diff --git a/lib/stwcs/wcsutil/mappings.py b/lib/stwcs/wcsutil/mappings.py
deleted file mode 100644
index 24038bf..0000000
--- a/lib/stwcs/wcsutil/mappings.py
+++ /dev/null
@@ -1,29 +0,0 @@
-from __future__ import division # confidence high
-
-# This dictionary maps an instrument into an instrument class
-# The instrument class handles instrument specific keywords
-
-inst_mappings={'WFPC2': 'WFPC2WCS',
-                'ACS': 'ACSWCS',
-                'NICMOS': 'NICMOSWCS',
-                'STIS': 'STISWCS',
-                'WFC3': 'WFC3WCS',
-                'DEFAULT': 'InstrWCS'
-                }
-
-
-# A list of instrument specific keywords
-# Every instrument class must have methods which define each of these
-# as class attributes.
-ins_spec_kw = [ 'idctab', 'offtab', 'date_obs', 'ra_targ', 'dec_targ', 'pav3', \
-                'detector', 'ltv1', 'ltv2', 'parity', 'binned','vafactor', \
-                'chip', 'naxis1', 'naxis2', 'filter1', 'filter2']
-
-# A list of keywords defined in the primary header.
-# The HSTWCS class sets this as attributes 
-prim_hdr_kw = ['detector', 'offtab', 'idctab', 'date-obs', 
-              'pa_v3', 'ra_targ', 'dec_targ']
-
-# These are the keywords which are archived before MakeWCS is run
-basic_wcs = ['CD1_', 'CD2_', 'CRVAL', 'CTYPE', 'CRPIX', 'CTYPE', 'CDELT', 'CUNIT']
-            
diff --git a/lib/stwcs/wcsutil/mosaic.py b/lib/stwcs/wcsutil/mosaic.py
deleted file mode 100644
index 9d2d0a3..0000000
--- a/lib/stwcs/wcsutil/mosaic.py
+++ /dev/null
@@ -1,183 +0,0 @@
-from __future__ import division, print_function
-import numpy as np
-from matplotlib import pyplot as plt
-from astropy.io import fits
-import string
-
-from stsci.tools import parseinput, irafglob
-from stwcs.distortion import utils
-from stwcs import updatewcs, wcsutil
-from stwcs.wcsutil import altwcs
-
-def vmosaic(fnames, outwcs=None, ref_wcs=None, ext=None, extname=None, undistort=True, wkey='V', wname='VirtualMosaic', plot=False, clobber=False):
-    """
-    Create a virtual mosaic using the WCS of the input images.
-
-    Parameters
-    ----------
-    fnames: a string or a list
-              a string or a list of filenames, or a list of wcsutil.HSTWCS objects
-    outwcs: an HSTWCS object
-             if given, represents the output tangent plane
-             if None, the output WCS is calculated from the input observations.
-    ref_wcs: an HSTWCS object
-             if output wcs is not given, this will be used as a reference for the
-             calculation of the output WCS. If ref_wcs is None and outwcs is None,
-             then the first observation in th einput list is used as reference.
-    ext:    an int, a tuple or a list
-              an int - represents a FITS extension, e.g. 0 is the primary HDU
-              a tuple - uses the notation (extname, extver), e.g. ('sci',1)
-              Can be a list of integers or tuples representing FITS extensions
-    extname: string
-              the value of the EXTNAME keyword for the extensions to be used in the mosaic
-    undistort: boolean (default: True)
-               undistort (or not) the output WCS
-    wkey:   string
-              default: 'V'
-              one character A-Z to be used to record the virtual mosaic WCS as
-              an alternate WCS in the headers of the input files.
-    wname:  string
-              default: 'VirtualMosaic
-              a string to be used as a WCSNAME value for the alternate WCS representign
-              the virtual mosaic
-    plot:   boolean
-              if True and matplotlib is installed will make a plot of the tangent plane
-              and the location of the input observations.
-    clobber: boolean
-              This covers the case when an alternate WCS with the requested key
-              already exists in the header of the input files.
-              if clobber is True, it will be overwritten
-              if False, it will compute the new one but will not write it to the headers.
-
-    Notes
-    -----
-    The algorithm is:
-    1. If output WCS is not given it is calculated from the input WCSes.
-       The first image is used as a reference, if no reference is given.
-       This represents the virtual mosaic WCS.
-    2. For each input observation/chip, an HSTWCS object is created
-       and its footprint on the sky is calculated (using only the four corners).
-    3. For each input observation the footprint is projected on the output
-       tangent plane and the virtual WCS is recorded in the header.
-    """
-    wcsobjects = readWCS(fnames, ext, extname)
-    if outwcs != None:
-        outwcs = outwcs.deepcopy()
-    else:
-        if ref_wcs != None:
-            outwcs = utils.output_wcs(wcsobjects, ref_wcs=ref_wcs, undistort=undistort)
-        else:
-            outwcs = utils.output_wcs(wcsobjects, undistort=undistort)
-    if plot:
-        outc=np.array([[0.,0], [outwcs._naxis1, 0],
-                             [outwcs._naxis1, outwcs._naxis2],
-                             [0, outwcs._naxis2], [0, 0]])
-        plt.plot(outc[:,0], outc[:,1])
-    for wobj in wcsobjects:
-        outcorners = outwcs.wcs_world2pix(wobj.calc_footprint(),1)
-        if plot:
-            plt.plot(outcorners[:,0], outcorners[:,1])
-        objwcs = outwcs.deepcopy()
-        objwcs.wcs.crpix = objwcs.wcs.crpix - (outcorners[0])
-        updatehdr(wobj.filename, objwcs,wkey=wkey, wcsname=wname, ext=wobj.extname, clobber=clobber)
-    return outwcs
-
-def updatehdr(fname, wcsobj, wkey, wcsname, ext=1, clobber=False):
-    hdr = fits.getheader(fname, ext=ext)
-    all_keys = list(string.ascii_uppercase)
-    if wkey.upper() not in all_keys:
-        raise KeyError("wkey must be one character: A-Z")
-    if wkey not in altwcs.available_wcskeys(hdr):
-        if not clobber:
-            raise ValueError("wkey %s is already in use. Use clobber=True to overwrite it or specify a different key." %wkey)
-        else:
-            altwcs.deleteWCS(fname, ext=ext, wcskey='V')
-    f = fits.open(fname, mode='update')
-
-    hwcs = wcs2header(wcsobj)
-    wcsnamekey = 'WCSNAME' + wkey
-    f[ext].header[wcsnamekey] = wcsname
-    for k in hwcs:
-        f[ext].header[k[:7]+wkey] = hwcs[k]
-
-    f.close()
-
-def wcs2header(wcsobj):
-
-    h = wcsobj.to_header()
-
-    if wcsobj.wcs.has_cd():
-        altwcs.pc2cd(h)
-    h['CTYPE1'] = 'RA---TAN'
-    h['CTYPE2'] = 'DEC--TAN'
-    norient = np.rad2deg(np.arctan2(h['CD1_2'],h['CD2_2']))
-    #okey = 'ORIENT%s' % wkey
-    okey = 'ORIENT'
-    h[okey] = norient
-    return h
-
-def readWCS(input, exts=None, extname=None):
-    if isinstance(input, str):
-        if input[0] == '@':
-            # input is an @ file
-            filelist = irafglob.irafglob(input)
-        else:
-            try:
-                filelist, output = parseinput.parseinput(input)
-            except IOError: raise
-    elif isinstance(input, list):
-        if isinstance(input[0], wcsutil.HSTWCS):
-            # a list of HSTWCS objects
-            return input
-        else:
-            filelist = input[:]
-    wcso = []
-    fomited = []
-    # figure out which FITS extension(s) to use
-    if exts == None and extname == None:
-        #Assume it's simple FITS and the data is in the primary HDU
-        for f in filelist:
-            try:
-                wcso = wcsutil.HSTWCS(f)
-            except AttributeError:
-                fomited.append(f)
-                continue
-    elif exts != None and validateExt(exts):
-        exts = [exts]
-        for f in filelist:
-            try:
-                wcso.extend([wcsutil.HSTWCS(f, ext=e) for e in exts])
-            except KeyError:
-                fomited.append(f)
-                continue
-    elif extname != None:
-        for f in filelist:
-            fobj = fits.open(f)
-            for i in range(len(fobj)):
-                try:
-                    ename = fobj[i].header['EXTNAME']
-                except KeyError:
-                    continue
-                if ename.lower() == extname.lower():
-                    wcso.append(wcsutil.HSTWCS(f,ext=i))
-                else:
-                    continue
-            fobj.close()
-    if fomited != []:
-        print("These files were skipped:")
-        for f in fomited:
-            print(f)
-    return wcso
-
-
-def validateExt(ext):
-    if not isinstance(ext, int) and not isinstance(ext, tuple) \
-       and not isinstance(ext, list):
-        print("Ext must be integer, tuple, a list of int extension numbers, \
-        or a list of tuples representing a fits extension, for example ('sci', 1).")
-        return False
-    else:
-        return True
-
-
-
diff --git a/lib/stwcs/wcsutil/wcscorr.py b/lib/stwcs/wcsutil/wcscorr.py
deleted file mode 100644
index 3f9b7d5..0000000
--- a/lib/stwcs/wcsutil/wcscorr.py
+++ /dev/null
@@ -1,668 +0,0 @@
-from __future__ import absolute_import, division, print_function
-
-import os,copy
-import numpy as np
-from astropy.io import fits
-
-import stwcs
-from stwcs.wcsutil import altwcs
-from stwcs.updatewcs import utils
-from stsci.tools import fileutil
-from . import convertwcs
-
-DEFAULT_WCS_KEYS = ['CRVAL1','CRVAL2','CRPIX1','CRPIX2',
-                    'CD1_1','CD1_2','CD2_1','CD2_2',
-                    'CTYPE1','CTYPE2','ORIENTAT']
-DEFAULT_PRI_KEYS = ['HDRNAME','SIPNAME','NPOLNAME','D2IMNAME','DESCRIP']
-COL_FITSKW_DICT = {'RMS_RA':'sci.crder1','RMS_DEC':'sci.crder2',
-                'NMatch':'sci.nmatch','Catalog':'sci.catalog'}
-
-###
-### WCSEXT table related keyword archive functions
-###
-def init_wcscorr(input, force=False):
-    """
-    This function will initialize the WCSCORR table if it is not already present,
-    and look for WCS keywords with a prefix of 'O' as the original OPUS
-    generated WCS as the initial row for the table or use the current WCS
-    keywords as initial row if no 'O' prefix keywords are found.
-
-    This function will NOT overwrite any rows already present.
-
-    This function works on all SCI extensions at one time.
-    """
-    # TODO: Create some sort of decorator or (for Python2.5) context for
-    # opening a FITS file and closing it when done, if necessary
-    if not isinstance(input, fits.HDUList):
-        # input must be a filename, so open as `astropy.io.fits.HDUList` object
-        fimg = fits.open(input, mode='update')
-        need_to_close = True
-    else:
-        fimg = input
-        need_to_close = False
-
-    # Do not try to generate a WCSCORR table for a simple FITS file
-    numsci = fileutil.countExtn(fimg)
-    if len(fimg) == 1 or numsci == 0:
-        return
-
-    enames = []
-    for e in fimg: enames.append(e.name)
-    if 'WCSCORR' in enames:
-        if not force:
-            return
-        else:
-            del fimg['wcscorr']
-    print('Initializing new WCSCORR table for ',fimg.filename())
-
-    used_wcskeys = altwcs.wcskeys(fimg['SCI', 1].header)
-
-    # define the primary columns of the WCSEXT table with initial rows for each
-    # SCI extension for the original OPUS solution
-    numwcs = len(used_wcskeys)
-    if numwcs == 0: numwcs = 1
-
-    # create new table with more rows than needed initially to make it easier to
-    # add new rows later
-    wcsext = create_wcscorr(descrip=True,numrows=numsci, padding=(numsci*numwcs) + numsci * 4)
-    # Assign the correct EXTNAME value to this table extension
-    wcsext.header['TROWS'] = (numsci * 2, 'Number of updated rows in table')
-    wcsext.header['EXTNAME'] = ('WCSCORR', 'Table with WCS Update history')
-    wcsext.header['EXTVER'] = 1
-
-    # define set of WCS keywords which need to be managed and copied to the table
-    wcs1 = stwcs.wcsutil.HSTWCS(fimg,ext=('SCI',1))
-    idc2header = True
-    if wcs1.idcscale is None:
-        idc2header = False
-    wcs_keywords = list(wcs1.wcs2header(idc2hdr=idc2header).keys())
-
-    prihdr = fimg[0].header
-    prihdr_keys = DEFAULT_PRI_KEYS
-    pri_funcs = {'SIPNAME':stwcs.updatewcs.utils.build_sipname,
-                 'NPOLNAME':stwcs.updatewcs.utils.build_npolname,
-                 'D2IMNAME':stwcs.updatewcs.utils.build_d2imname}
-
-    # Now copy original OPUS values into table
-    for extver in range(1, numsci + 1):
-        rowind = find_wcscorr_row(wcsext.data,
-                                  {'WCS_ID': 'OPUS', 'EXTVER': extver,
-                                   'WCS_key':'O'})
-        # There should only EVER be a single row for each extension with OPUS values
-        rownum = np.where(rowind)[0][0]
-        #print 'Archiving OPUS WCS in row number ',rownum,' in WCSCORR table for SCI,',extver
-
-        hdr = fimg['SCI', extver].header
-        # define set of WCS keywords which need to be managed and copied to the table
-        if used_wcskeys is None:
-            used_wcskeys = altwcs.wcskeys(hdr)
-        # Check to see whether or not there is an OPUS alternate WCS present,
-        # if so, get its values directly, otherwise, archive the PRIMARY WCS
-        # as the OPUS values in the WCSCORR table
-        if 'O' not in used_wcskeys:
-            altwcs.archiveWCS(fimg,('SCI',extver),wcskey='O', wcsname='OPUS')
-        wkey = 'O'
-
-        wcs = stwcs.wcsutil.HSTWCS(fimg, ext=('SCI', extver), wcskey=wkey)
-        wcshdr = wcs.wcs2header(idc2hdr=idc2header)
-
-        if wcsext.data.field('CRVAL1')[rownum] != 0:
-            # If we find values for these keywords already in the table, do not
-            # overwrite them again
-            print('WCS keywords already updated...')
-            break
-        for key in wcs_keywords:
-            if key in wcsext.data.names:
-                wcsext.data.field(key)[rownum] = wcshdr[(key+wkey)[:8]]
-        # Now get any keywords from PRIMARY header needed for WCS updates
-        for key in prihdr_keys:
-            if key in prihdr:
-                val = prihdr[key]
-            else:
-                val = ''
-            wcsext.data.field(key)[rownum] = val
-
-    # Now that we have archived the OPUS alternate WCS, remove it from the list
-    # of used_wcskeys
-    if 'O' in used_wcskeys:
-        used_wcskeys.remove('O')
-
-    # Now copy remaining alternate WCSs into table
-    # TODO: Much of this appears to be redundant with update_wcscorr; consider
-    # merging them...
-    for uwkey in used_wcskeys:
-        for extver in range(1, numsci + 1):
-            hdr = fimg['SCI', extver].header
-            wcs = stwcs.wcsutil.HSTWCS(fimg, ext=('SCI', extver),
-                                       wcskey=uwkey)
-            wcshdr = wcs.wcs2header()
-            if 'WCSNAME' + uwkey not in wcshdr:
-                wcsid = utils.build_default_wcsname(fimg[0].header['idctab'])
-            else:
-                wcsid = wcshdr['WCSNAME' + uwkey]
-
-            # identify next empty row
-            rowind = find_wcscorr_row(wcsext.data,
-                                    selections={'wcs_id':['','0.0']})
-            rows = np.where(rowind)
-            if len(rows[0]) > 0:
-                rownum = np.where(rowind)[0][0]
-            else:
-                print('No available rows found for updating. ')
-
-            # Update selection columns for this row with relevant values
-            wcsext.data.field('WCS_ID')[rownum] = wcsid
-            wcsext.data.field('EXTVER')[rownum] = extver
-            wcsext.data.field('WCS_key')[rownum] = uwkey
-
-            # Look for standard WCS keyword values
-            for key in wcs_keywords:
-                if key in wcsext.data.names:
-                    wcsext.data.field(key)[rownum] = wcshdr[key + uwkey]
-            # Now get any keywords from PRIMARY header needed for WCS updates
-            for key in prihdr_keys:
-                if key in pri_funcs:
-                    val = pri_funcs[key](fimg)[0]
-                else:
-                    if key in prihdr:
-                        val = prihdr[key]
-                    else:
-                        val = ''
-                wcsext.data.field(key)[rownum] = val
-
-    # Append this table to the image FITS file
-    fimg.append(wcsext)
-    # force an update now
-    # set the verify flag to 'warn' so that it will always succeed, but still
-    # tell the user if PyFITS detects any problems with the file as a whole
-    utils.updateNEXTENDKw(fimg)
-
-    fimg.flush('warn')
-
-    if need_to_close:
-        fimg.close()
-
-
-def find_wcscorr_row(wcstab, selections):
-    """
-    Return an array of indices from the table (NOT HDU) 'wcstab' that matches the
-    selections specified by the user.
-
-    The row selection criteria must be specified as a dictionary with
-    column name as key and value(s) representing the valid desired row values.
-    For example, {'wcs_id':'OPUS','extver':2}.
-    """
-
-    mask = None
-    for i in selections:
-        icol = wcstab.field(i)
-        if isinstance(icol,np.chararray): icol = icol.rstrip()
-        selecti = selections[i]
-        if not isinstance(selecti,list):
-            if isinstance(selecti,str):
-                selecti = selecti.rstrip()
-            bmask = (icol == selecti)
-            if mask is None:
-                mask = bmask.copy()
-            else:
-                mask = np.logical_and(mask,bmask)
-            del bmask
-        else:
-            for si in selecti:
-                if isinstance(si,str):
-                    si = si.rstrip()
-                bmask = (icol == si)
-                if mask is None:
-                    mask = bmask.copy()
-                else:
-                    mask = np.logical_or(mask,bmask)
-                del bmask
-
-    return mask
-
-
-def archive_wcs_file(image, wcs_id=None):
-    """
-    Update WCSCORR table with rows for each SCI extension to record the
-    newly updated WCS keyword values.
-    """
-
-    if not isinstance(image, fits.HDUList):
-        fimg = fits.open(image, mode='update')
-        close_image = True
-    else:
-        fimg = image
-        close_image = False
-
-    update_wcscorr(fimg, wcs_id=wcs_id)
-
-    if close_image:
-        fimg.close()
-
-
-def update_wcscorr(dest, source=None, extname='SCI', wcs_id=None, active=True):
-    """
-    Update WCSCORR table with a new row or rows for this extension header. It
-    copies the current set of WCS keywords as a new row of the table based on
-    keyed WCSs as per Paper I Multiple WCS standard).
-
-    Parameters
-    ----------
-    dest : HDUList
-        The HDU list whose WCSCORR table should be appended to (the WCSCORR HDU
-        must already exist)
-    source : HDUList, optional
-        The HDU list containing the extension from which to extract the WCS
-        keywords to add to the WCSCORR table.  If None, the dest is also used
-        as the source.
-    extname : str, optional
-        The extension name from which to take new WCS keywords.  If there are
-        multiple extensions with that name, rows are added for each extension
-        version.
-    wcs_id : str, optional
-        The name of the WCS to add, as in the WCSNAMEa keyword.  If
-        unspecified, all the WCSs in the specified extensions are added.
-    active: bool, optional
-        When True, indicates that the update should reflect an update of the
-        active WCS information, not just appending the WCS to the file as a
-        headerlet
-    """
-    if not isinstance(dest, fits.HDUList):
-        dest = fits.open(dest,mode='update')
-    fname = dest.filename()
-
-    if source is None:
-        source = dest
-
-    if extname == 'PRIMARY':
-        return
-
-    numext = fileutil.countExtn(source, extname)
-    if numext == 0:
-        raise ValueError('No %s extensions found in the source HDU list.'
-                        % extname)
-    # Initialize the WCSCORR table extension in dest if not already present
-    init_wcscorr(dest)
-    try:
-        dest.index_of('WCSCORR')
-    except KeyError:
-        return
-
-    # check to see whether or not this is an up-to-date table
-    # replace with newly initialized table with current format
-    old_table = dest['WCSCORR']
-    wcscorr_cols = ['WCS_ID','EXTVER', 'SIPNAME',
-                    'HDRNAME', 'NPOLNAME', 'D2IMNAME']
-
-    for colname in wcscorr_cols:
-        if colname not in old_table.data.columns.names:
-            print("WARNING:    Replacing outdated WCSCORR table...")
-            outdated_table = old_table.copy()
-            del dest['WCSCORR']
-            init_wcscorr(dest)
-            old_table = dest['WCSCORR']
-            break
-
-    # Current implementation assumes the same WCS keywords are in each
-    # extension version; if this should not be assumed then this can be
-    # modified...
-    wcs_keys = altwcs.wcskeys(source[(extname, 1)].header)
-    wcs_keys = [kk for kk in wcs_keys if kk]
-    if ' ' not in wcs_keys: wcs_keys.append(' ') # Insure that primary WCS gets used
-    # apply logic for only updating WCSCORR table with specified keywords
-    # corresponding to the WCS with WCSNAME=wcs_id
-    if wcs_id is not None:
-        wnames = altwcs.wcsnames(source[(extname, 1)].header)
-        wkeys = []
-        for letter in wnames:
-            if wnames[letter] == wcs_id:
-                wkeys.append(letter)
-        if len(wkeys) > 1 and ' ' in wkeys:
-            wkeys.remove(' ')
-        wcs_keys = wkeys
-    wcshdr = stwcs.wcsutil.HSTWCS(source, ext=(extname, 1)).wcs2header()
-    wcs_keywords = list(wcshdr.keys())
-
-    if 'O' in wcs_keys:
-        wcs_keys.remove('O') # 'O' is reserved for original OPUS WCS
-
-    # create new table for hdr and populate it with the newly updated values
-    new_table = create_wcscorr(descrip=True,numrows=0, padding=len(wcs_keys)*numext)
-    prihdr = source[0].header
-
-    # Get headerlet related keywords here
-    sipname, idctab = utils.build_sipname(source, fname, "None")
-    npolname, npolfile = utils.build_npolname(source, None)
-    d2imname, d2imfile = utils.build_d2imname(source, None)
-    if 'hdrname' in prihdr:
-        hdrname = prihdr['hdrname']
-    else:
-        hdrname = ''
-
-    idx = -1
-    for wcs_key in wcs_keys:
-        for extver in range(1, numext + 1):
-            extn = (extname, extver)
-            if 'SIPWCS' in extname and not active:
-                tab_extver = 0 # Since it has not been added to the SCI header yet
-            else:
-                tab_extver = extver
-            hdr = source[extn].header
-            if 'WCSNAME'+wcs_key in hdr:
-                wcsname = hdr['WCSNAME' + wcs_key]
-            else:
-                wcsname = utils.build_default_wcsname(hdr['idctab'])
-
-            selection = {'WCS_ID': wcsname, 'EXTVER': tab_extver,
-                         'SIPNAME':sipname, 'HDRNAME': hdrname,
-                         'NPOLNAME': npolname, 'D2IMNAME':d2imname
-                         }
-
-            # Ensure that an entry for this WCS is not already in the dest
-            # table; if so just skip it
-            rowind = find_wcscorr_row(old_table.data, selection)
-            if np.any(rowind):
-                continue
-
-            idx += 1
-
-            wcs = stwcs.wcsutil.HSTWCS(source, ext=extn, wcskey=wcs_key)
-            wcshdr = wcs.wcs2header()
-
-            # Update selection column values
-            for key, val in selection.items():
-                if key in new_table.data.names:
-                    new_table.data.field(key)[idx] = val
-
-            for key in wcs_keywords:
-                if key in new_table.data.names:
-                    new_table.data.field(key)[idx] = wcshdr[key + wcs_key]
-
-            for key in DEFAULT_PRI_KEYS:
-                if key in new_table.data.names and key in prihdr:
-                    new_table.data.field(key)[idx] = prihdr[key]
-            # Now look for additional, non-WCS-keyword table column data
-            for key in COL_FITSKW_DICT:
-                fitkw = COL_FITSKW_DICT[key]
-                # Interpret any 'pri.hdrname' or
-                # 'sci.crpix1' formatted keyword names
-                if '.' in fitkw:
-                    srchdr,fitkw = fitkw.split('.')
-                    if 'pri' in srchdr.lower(): srchdr = prihdr
-                    else: srchdr = source[extn].header
-                else:
-                    srchdr = source[extn].header
-
-                if fitkw+wcs_key in srchdr:
-                    new_table.data.field(key)[idx] = srchdr[fitkw+wcs_key]
-
-
-    # If idx was never incremented, no rows were added, so there's nothing else
-    # to do...
-    if idx < 0:
-        return
-
-    # Now, we need to merge this into the existing table
-    rowind = find_wcscorr_row(old_table.data, {'wcs_id':['','0.0']})
-    old_nrows = np.where(rowind)[0][0]
-    new_nrows = new_table.data.shape[0]
-
-    # check to see if there is room for the new row
-    if (old_nrows + new_nrows) > old_table.data.shape[0]-1:
-        pad_rows = 2 * new_nrows
-        # if not, create a new table with 'pad_rows' new empty rows
-        upd_table = fits.new_table(old_table.columns,header=old_table.header,
-                                     nrows=old_table.data.shape[0]+pad_rows)
-    else:
-        upd_table = old_table
-        pad_rows = 0
-    # Now, add
-    for name in old_table.columns.names:
-        if name in new_table.data.names:
-            # reset the default values to ones specific to the row definitions
-            for i in range(pad_rows):
-                upd_table.data.field(name)[old_nrows+i] = old_table.data.field(name)[-1]
-            # Now populate with values from new table
-            upd_table.data.field(name)[old_nrows:old_nrows + new_nrows] = \
-                    new_table.data.field(name)
-    upd_table.header['TROWS'] = old_nrows + new_nrows
-
-    # replace old extension with newly updated table extension
-    dest['WCSCORR'] = upd_table
-
-
-def restore_file_from_wcscorr(image, id='OPUS', wcskey=''):
-    """ Copies the values of the WCS from the WCSCORR based on ID specified by user.
-    The default will be to restore the original OPUS-derived values to the Primary WCS.
-    If wcskey is specified, the WCS with that key will be updated instead.
-    """
-
-    if not isinstance(image, fits.HDUList):
-        fimg = fits.open(image, mode='update')
-        close_image = True
-    else:
-        fimg = image
-        close_image = False
-    numsci = fileutil.countExtn(fimg)
-    wcs_table = fimg['WCSCORR']
-    orig_rows = (wcs_table.data.field('WCS_ID') == 'OPUS')
-    # create an HSTWCS object to figure out what WCS keywords need to be updated
-    wcsobj = stwcs.wcsutil.HSTWCS(fimg,ext=('sci',1))
-    wcshdr = wcsobj.wcs2header()
-    for extn in range(1,numsci+1):
-        # find corresponding row from table
-        ext_rows = (wcs_table.data.field('EXTVER') == extn)
-        erow = np.where(np.logical_and(ext_rows,orig_rows))[0][0]
-        for key in wcshdr:
-            if key in wcs_table.data.names: # insure that keyword is column in table
-                tkey = key
-
-                if 'orient' in key.lower():
-                    key = 'ORIENT'
-                if wcskey == '':
-                    skey = key
-                else:
-                    skey = key[:7]+wcskey
-                fimg['sci',extn].header[skey] = wcs_table.data.field(tkey)[erow]
-        for key in DEFAULT_PRI_KEYS:
-            if key in wcs_table.data.names:
-                if wcskey == '':
-                    pkey = key
-                else:
-                    pkey = key[:7]+wcskey
-                fimg[0].header[pkey] = wcs_table.data.field(key)[erow]
-
-    utils.updateNEXTENDKw(fimg)
-
-    # close the image now that the update has been completed.
-    if close_image:
-        fimg.close()
-
-
-def create_wcscorr(descrip=False, numrows=1, padding=0):
-    """
-    Return the basic definitions for a WCSCORR table.
-    The dtype definitions for the string columns are set to the maximum allowed so
-    that all new elements will have the same max size which will be automatically
-    truncated to this limit upon updating (if needed).
-
-    The table is initialized with rows corresponding to the OPUS solution
-    for all the 'SCI' extensions.
-    """
-
-    trows = numrows + padding
-    # define initialized arrays as placeholders for column data
-    # TODO: I'm certain there's an easier way to do this... for example, simply
-    # define the column names and formats, then create an empty array using
-    # them as a dtype, then create the new table from that array.
-    def_float64_zeros = np.array([0.0] * trows, dtype=np.float64)
-    def_float64_ones = def_float64_zeros + 1.0
-    def_float_col = {'format': 'D', 'array': def_float64_zeros.copy()}
-    def_float1_col = {'format': 'D', 'array':def_float64_ones.copy()}
-    def_str40_col = {'format': '40A',
-                     'array': np.array([''] * trows, dtype='S40')}
-    def_str24_col = {'format': '24A',
-                     'array': np.array([''] * trows, dtype='S24')}
-    def_int32_col = {'format': 'J',
-                     'array': np.array([0]*trows,dtype=np.int32)}
-
-    # If more columns are needed, simply add their definitions to this list
-    col_names = [('HDRNAME',  def_str24_col), ('SIPNAME',   def_str24_col),
-                 ('NPOLNAME', def_str24_col), ('D2IMNAME',  def_str24_col),
-                 ('CRVAL1',   def_float_col), ('CRVAL2',    def_float_col),
-                 ('CRPIX1',   def_float_col), ('CRPIX2',    def_float_col),
-                 ('CD1_1',    def_float_col), ('CD1_2',     def_float_col),
-                 ('CD2_1',    def_float_col), ('CD2_2',     def_float_col),
-                 ('CTYPE1',   def_str24_col), ('CTYPE2',    def_str24_col),
-                 ('ORIENTAT', def_float_col), ('PA_V3',     def_float_col),
-                 ('RMS_RA',   def_float_col), ('RMS_Dec',   def_float_col),
-                 ('NMatch',   def_int32_col), ('Catalog',   def_str40_col)]
-
-    # Define selector columns
-    id_col = fits.Column(name='WCS_ID', format='40A',
-                         array=np.array(['OPUS'] * numrows + [''] * padding,
-                                        dtype='S24'))
-    extver_col = fits.Column(name='EXTVER', format='I',
-                             array=np.array(list(range(1, numrows + 1)),
-                                            dtype=np.int16))
-    wcskey_col = fits.Column(name='WCS_key', format='A',
-                             array=np.array(['O'] * numrows + [''] * padding,
-                                            dtype='S'))
-    # create list of remaining columns to be added to table
-    col_list = [id_col, extver_col, wcskey_col] # start with selector columns
-
-    for c in col_names:
-        cdef = copy.deepcopy(c[1])
-        col_list.append(fits.Column(name=c[0], format=cdef['format'],
-                        array=cdef['array']))
-
-    if descrip:
-        col_list.append(
-            fits.Column(name='DESCRIP', format='128A',
-                        array=np.array(
-                            ['Original WCS computed by OPUS'] * numrows,
-                            dtype='S128')))
-
-    # Now create the new table from the column definitions
-    newtab = fits.new_table(fits.ColDefs(col_list), nrows=trows)
-    # The fact that setting .name is necessary should be considered a bug in
-    # pyfits.
-    # TODO: Make sure this is fixed in pyfits, then remove this
-    newtab.name = 'WCSCORR'
-
-    return newtab
-
-def delete_wcscorr_row(wcstab,selections=None,rows=None):
-    """
-    Sets all values in a specified row or set of rows to default values
-
-    This function will essentially erase the specified row from the table
-    without actually removing the row from the table. This avoids the problems
-    with trying to resize the number of rows in the table while preserving the
-    ability to update the table with new rows again without resizing the table.
-
-    Parameters
-    ----------
-    wcstab: object
-        PyFITS binTable object for WCSCORR table
-    selections: dict
-        Dictionary of wcscorr column names and values to be used to select
-        the row or set of rows to erase
-    rows: int, list
-        If specified, will specify what rows from the table to erase regardless
-        of the value of 'selections'
-    """
-
-    if selections is None and rows is None:
-        print('ERROR: Some row selection information must be provided!')
-        print('       Either a row numbers or "selections" must be provided.')
-        raise ValueError
-
-    delete_rows = None
-    if rows is None:
-        if 'wcs_id' in selections and selections['wcs_id'] == 'OPUS':
-            delete_rows = None
-            print('WARNING: OPUS WCS information can not be deleted from WCSCORR table.')
-            print('         This row will not be deleted!')
-        else:
-            rowind = find_wcscorr_row(wcstab, selections=selections)
-            delete_rows = np.where(rowind)[0].tolist()
-    else:
-        if not isinstance(rows,list):
-            rows = [rows]
-        delete_rows = rows
-
-    # Insure that rows pointing to OPUS WCS do not get deleted, even by accident
-    for row in delete_rows:
-        if wcstab['WCS_key'][row] == 'O' or wcstab['WCS_ID'][row] == 'OPUS':
-            del delete_rows[delete_rows.index(row)]
-
-    if delete_rows is None:
-        return
-
-    # identify next empty row
-    rowind = find_wcscorr_row(wcstab, selections={'wcs_id':['','0.0']})
-    last_blank_row = np.where(rowind)[0][-1]
-
-    # copy values from blank row into user-specified rows
-    for colname in wcstab.names:
-        wcstab[colname][delete_rows] = wcstab[colname][last_blank_row]
-
-def update_wcscorr_column(wcstab, column, values, selections=None, rows=None):
-    """
-    Update the values in 'column' with 'values' for selected rows
-
-    Parameters
-    ----------
-    wcstab: object
-        PyFITS binTable object for WCSCORR table
-    column: string
-        Name of table column with values that need to be updated
-    values: string, int, or list
-        Value or set of values to copy into the selected rows for the column
-    selections: dict
-        Dictionary of wcscorr column names and values to be used to select
-        the row or set of rows to erase
-    rows: int, list
-        If specified, will specify what rows from the table to erase regardless
-        of the value of 'selections'
-    """
-    if selections is None and rows is None:
-        print('ERROR: Some row selection information must be provided!')
-        print('       Either a row numbers or "selections" must be provided.')
-        raise ValueError
-
-    if not isinstance(values, list):
-        values = [values]
-
-    update_rows = None
-    if rows is None:
-        if 'wcs_id' in selections and selections['wcs_id'] == 'OPUS':
-            update_rows = None
-            print('WARNING: OPUS WCS information can not be deleted from WCSCORR table.')
-            print('         This row will not be deleted!')
-        else:
-            rowind = find_wcscorr_row(wcstab, selections=selections)
-            update_rows = np.where(rowind)[0].tolist()
-    else:
-        if not isinstance(rows,list):
-            rows = [rows]
-        update_rows = rows
-
-    if update_rows is None:
-        return
-
-    # Expand single input value to apply to all selected rows
-    if len(values) > 1 and len(values) < len(update_rows):
-        print('ERROR: Number of new values',len(values))
-        print('       does not match number of rows',len(update_rows),' to be updated!')
-        print('       Please enter either 1 value or the same number of values')
-        print('       as there are rows to be updated.')
-        print('    Table will not be updated...')
-        raise ValueError
-
-    if len(values) == 1 and len(values) < len(update_rows):
-        values = values * len(update_rows)
-    # copy values from blank row into user-specified rows
-    for row in update_rows:
-        wcstab[column][row] = values[row]
diff --git a/lib/stwcs/wcsutil/wcsdiff.py b/lib/stwcs/wcsutil/wcsdiff.py
deleted file mode 100644
index cfc2d66..0000000
--- a/lib/stwcs/wcsutil/wcsdiff.py
+++ /dev/null
@@ -1,150 +0,0 @@
-from __future__ import print_function
-from astropy import wcs as pywcs
-from collections import OrderedDict
-from astropy.io import fits
-from .headerlet import parse_filename
-import numpy as np
-
-def is_wcs_identical(scifile, file2, sciextlist, fextlist, scikey=" ",
-                     file2key=" ", verbose=False):
-    """
-    Compares the WCS solution of 2 files.
-
-    Parameters
-    ----------
-    scifile: string
-             name of file1 (usually science file)
-             IRAF style extension syntax is accepted as well
-             for example scifile[1] or scifile[sci,1]
-    file2:   string
-             name of second file (for example headerlet)
-    sciextlist - list
-             a list of int or tuple ('SCI', 1), extensions in the first file
-    fextlist - list
-             a list of int or tuple ('SIPWCS', 1), extensions in the second file
-    scikey:  string
-             alternate WCS key in scifile
-    file2key: string
-             alternate WCS key in file2
-    verbose: boolean
-             True: print to stdout
-
-    Notes
-    -----
-    These can be 2 science observations or 2 headerlets
-    or a science observation and a headerlet. The two files
-    have the same WCS solution if the following are the same:
-
-    - rootname/destim
-    - primary WCS
-    - SIP coefficients
-    - NPOL distortion
-    - D2IM correction
-
-    """
-    result = True
-    diff = OrderedDict()
-    fobj, fname, close_file = parse_filename(file2)
-    sciobj, sciname, close_scifile = parse_filename(scifile)
-    diff['file_names'] = [scifile, file2]
-    if get_rootname(scifile) != get_rootname(file2):
-        #logger.info('Rootnames do not match.')
-        diff['rootname'] = ("%s: %s", "%s: %s") % (sciname, get_rootname(scifile), file2, get_rootname(file2))
-        result = False
-    for i, j in zip(sciextlist, fextlist):
-        w1 = pywcs.WCS(sciobj[i].header, sciobj, key=scikey)
-        w2 = pywcs.WCS(fobj[j].header, fobj, key=file2key)
-        diff['extension'] = [get_extname_extnum(sciobj[i]), get_extname_extnum(fobj[j])]
-        if not np.allclose(w1.wcs.crval, w2.wcs.crval, rtol=10**(-7)):
-            #logger.info('CRVALs do not match')
-            diff['CRVAL'] = w1.wcs.crval, w2.wcs.crval
-            result = False
-        if not np.allclose(w1.wcs.crpix, w2.wcs.crpix, rtol=10**(-7)):
-            #logger.info('CRPIX do not match')
-            diff ['CRPIX'] = w1.wcs.crpix, w2.wcs.crpix
-            result = False
-        if not np.allclose(w1.wcs.cd, w2.wcs.cd, rtol=10**(-7)):
-            #logger.info('CDs do not match')
-            diff ['CD'] = w1.wcs.cd, w2.wcs.cd
-            result = False
-        if not (np.array(w1.wcs.ctype) == np.array(w2.wcs.ctype)).all():
-            #logger.info('CTYPEs do not match')
-            diff ['CTYPE'] = w1.wcs.ctype,  w2.wcs.ctype
-            result = False
-        if w1.sip or w2.sip:
-            if (w2.sip and not w1.sip) or (w1.sip and not w2.sip):
-                diff['sip'] = 'one sip extension is missing'
-                result = False
-            if not np.allclose(w1.sip.a, w2.sip.a, rtol=10**(-7)):
-                diff['SIP_A'] = 'SIP_A differ'
-                result = False
-            if not np.allclose(w1.sip.b, w2.sip.b, rtol=10**(-7)):
-                #logger.info('SIP coefficients do not match')
-                diff ['SIP_B'] = (w1.sip.b, w2.sip.b)
-                result = False
-        if w1.cpdis1 or w2.cpdis1:
-            if w1.cpdis1 and not w2.cpdis1 or w2.cpdis1 and not w1.cpdis1:
-                diff['CPDIS1'] = "CPDIS1 missing"
-                result=False
-            if w1.cpdis2 and not w2.cpdis2 or w2.cpdis2 and not w1.cpdis2:
-                diff['CPDIS2'] = "CPDIS2 missing"
-                result = False
-            if not np.allclose(w1.cpdis1.data, w2.cpdis1.data, rtol=10**(-7)):
-                #logger.info('NPOL distortions do not match')
-                diff ['CPDIS1_data'] = (w1.cpdis1.data, w2.cpdis1.data)
-                result = False
-            if not np.allclose(w1.cpdis2.data, w2.cpdis2.data, rtol=10**(-7)):
-                #logger.info('NPOL distortions do not match')
-                diff ['CPDIS2_data'] = (w1.cpdis2.data, w2.cpdis2.data)
-                result = False
-        if w1.det2im1 or w2.det2im1:
-            if w1.det2im1 and not w2.det2im1 or \
-                w2.det2im1 and not w1.det2im1:
-                diff['DET2IM'] = "Det2im1 missing"
-                result = False
-            if not np.allclose(w1.det2im1.data, w2.det2im1.data, rtol=10**(-7)):
-                #logger.info('Det2Im corrections do not match')
-                diff ['D2IM1_data'] = (w1.det2im1.data, w2.det2im1.data)
-                result =  False
-        if w1.det2im2 or w2.det2im2:
-            if w1.det2im2 and not w2.det2im2 or \
-               w2.det2im2 and not w1.det2im2:
-                diff['DET2IM2'] = "Det2im2 missing"
-                result = False
-            if not np.allclose(w1.det2im2.data, w2.det2im2.data, rtol=10**(-7)):
-                #logger.info('Det2Im corrections do not match')
-                diff ['D2IM2_data'] = (w1.det2im2.data, w2.det2im2.data)
-                result = False
-    if not result and verbose:
-        for key in diff:
-            print(key, ":\t", diff[key][0], "\t", diff[key][1])
-    if close_file:
-        fobj.close()
-    if close_scifile:
-        sciobj.close()
-    return result, diff
-
-def get_rootname(fname):
-    """
-    Returns the value of ROOTNAME or DESTIM
-    """
-
-    hdr = fits.getheader(fname)
-    try:
-        rootname = hdr['ROOTNAME']
-    except KeyError:
-        try:
-            rootname = hdr['DESTIM']
-        except KeyError:
-            rootname = fname
-    return rootname
-
-def get_extname_extnum(ext):
-    """
-    Return (EXTNAME, EXTNUM) of a FITS extension
-    """
-    extname = ""
-    extnum=1
-    extname = ext.header.get('EXTNAME', extname)
-    extnum = ext.header.get('EXTVER', extnum)
-    return (extname, extnum)