diff options
| -rw-r--r-- | updatewcs/makewcs.py | 84 |
1 files changed, 36 insertions, 48 deletions
diff --git a/updatewcs/makewcs.py b/updatewcs/makewcs.py index d2a3cb6..4b06d95 100644 --- a/updatewcs/makewcs.py +++ b/updatewcs/makewcs.py @@ -1,7 +1,6 @@ #from .. mappings import DEGTORAD, RADTODEG from hstwcs.mappings import DEGTORAD, RADTODEG import numpy -from numpy import math from math import sin, sqrt, pow, cos, asin, atan2,pi from hstwcs import utils from pytools import fileutil @@ -10,13 +9,25 @@ class MakeWCS(object): """ Purpose ======= - Recompute WCS keywords based on PA_V3 and distortion model. + Recompute basic WCS keywords based on PA_V3 and distortion model. Algorithm ========= - update reference chip wcs + + -- CRVAL: reference chip model zero point (XREF/YREF) on 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 + - update extension wcs - - update extension header + + -- 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) """ tdd_xyref = {1: [2048, 3072], 2:[2048, 1024]} @@ -60,12 +71,11 @@ class MakeWCS(object): else: fx, fy = ext_wcs.idcmodel.cx, ext_wcs.idcmodel.cy - ridcmodel = ref_wcs.idcmodel - - v2 = ext_wcs.idcmodel.refpix['V2REF'] + v23_corr[0,0] - v3 = ext_wcs.idcmodel.refpix['V3REF'] - v23_corr[1,0] - v2ref = ref_wcs.idcmodel.refpix['V2REF'] + rv23_corr[0,0] - v3ref = ref_wcs.idcmodel.refpix['V3REF'] - rv23_corr[1,0] + 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) @@ -87,54 +97,34 @@ class MakeWCS(object): ext_wcs.wcs.crval = newcrval ext_wcs.wcs.crpix = newcrpix ext_wcs.wcs.set() + + # Create a small vector, in reference image pixel scale + delmat = numpy.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 - - - # Create a small vector, in reference image pixel scale - # There is no parity effect here ??? - - delXX=fx[1,1]/R_scale/3600. - delYX=fy[1,1]/R_scale/3600. - delXY=fx[1,0]/R_scale/3600. - delYY=fy[1,0]/R_scale/3600. - + dtheta = 0.0 # Convert to radians rr=dtheta*pi/180.0 + rrmat = fileutil.buildRotMatrix(rr) # Rotate the vectors - dXX = cos(rr)*delXX - sin(rr)*delYX - dYX = sin(rr)*delXX + cos(rr)*delYX - - dXY = cos(rr)*delXY - sin(rr)*delYY - dYY = sin(rr)*delXY + cos(rr)*delYY - - px = numpy.array([[dX+dXX,dY+dYX]]) - - # Transform to sky coordinates - wc = ref_wcs.wcs.p2s_fits(px)['world'] - - a = wc[0,0] - b = wc[0,1] - px = numpy.array([[dX+dXY,dY+dYY]]) - - wc = ref_wcs.wcs.p2s_fits(px)['world'] - - c = wc[0,0] - d = wc[0,1] + dxy = numpy.dot(rrmat, delmat) + wc = ref_wcs.wcs.p2s_fits(px + dxy)['world'] # Calculate the new CDs and convert to degrees - cd11 = utils.diff_angles(a,newcrval[0])*cos(newcrval[1]*pi/180.0) - cd12 = utils.diff_angles(c,newcrval[0])*cos(newcrval[1]*pi/180.0) - cd21 = utils.diff_angles(b,newcrval[1]) - cd22 = utils.diff_angles(d,newcrval[1]) + 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 = numpy.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): @@ -144,9 +134,9 @@ class MakeWCS(object): ltvoffx, ltvoffy = loff[0], loff[1] offshift = offsh dec = ref_wcs.wcs.crval[1] - - rv23 = [ref_wcs.idcmodel.refpix['V2REF'] + rv23_corr_tdd[0,0], - ref_wcs.idcmodel.refpix['V3REF'] - rv23_corr_tdd[1,0]] + tddscale = (ref_wcs.pscale/ext_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 = numpy.array([[ref_wcs.idcmodel.refpix['XREF']+ltvoffx , ref_wcs.idcmodel.refpix['YREF']+ltvoffy]]) @@ -157,7 +147,6 @@ class MakeWCS(object): # 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'] @@ -189,7 +178,6 @@ class MakeWCS(object): tdd = numpy.array([[beta, alpha], [alpha, -beta]]) mrotp = fileutil.buildRotMatrix(2.234529)/2048. xy0 = numpy.array([[cls.tdd_xyref[hwcs.chip][0]-2048.], [cls.tdd_xyref[hwcs.chip][1]-2048.]]) - v23_corr = numpy.dot(mrotp,numpy.dot(tdd,xy0)) * 0.05 return v23_corr |