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+.nr PS 9
+.nr VS 11
+.de LS
+.RT
+.if \\n(1T .sp \\n(PDu
+.ne 1.1
+.if !\\n(IP .nr IP +1
+.if \\n(.$-1 .nr I\\n(IR \\$2n
+.in +\\n(I\\n(IRu
+.ta \\n(I\\n(IRu
+.if \\n(.$ \{\
+.ds HT \&\\$1
+.ti -\\n(I\\n(IRu
+\\*(HT
+.br
+..
+.ND
+.TL
+ONEDSPEC/IMRED Package Revisions Summary: IRAF Version 2.10
+.AU
+Francisco Valdes
+.AI
+IRAF Group - Central Computer Services
+.K2
+P.O. Box 26732, Tucson, Arizona 85726
+May 1992
+.NH
+Introduction
+.LP
+The IRAF NOAO spectroscopy software, except for the \fBlongslit\fR
+package, has undergone major revisions.  The revisions to the aperture
+extraction package, \fBapextract\fR, are described in a separate
+document.  This paper addresses the revisions in the \fBonedspec\fR
+package and the spectroscopic image reduction packages in the
+\fBimred\fR package.  In addition to the revisions summary given here
+there is a new help topic covering general aspects of the new
+\fBonedspec\fR package such as image formats, coordinate systems, and
+units.  This help topic is referenced under the name
+"onedspec.package".
+.LP
+There are a large number of revisions both minor and major.  To avoid
+obscuring the basic themes and the major revisions in a wealth of minor
+detail, this document is organized into sections of increasing detail.  The
+most important aspects of the revisions are described in a major highlight
+section followed by a minor highlight section.  Then a reorganization chart
+for the \fBonedspec\fR package is presented showing where various
+tasks have been moved, which have been deleted, and which are new.
+Finally, a summary of the revisions to each task is presented.
+.LP
+I hope that the many new capabilities, particularly as presented in the
+highlight section, will outweigh any disruption in accomodating to so
+many changes.
+.NH
+Major Highlights
+.LP
+The major highlights of the revisions to the NOAO spectroscopy software
+are listed and then discussed below.
+
+.DS
+\(bu Non-linear dispersion calibration
+\(bu Integration of dispersion coordinates with the core system 
+\(bu Sinc interpolation
+\(bu Plotting in user selected units including velocity
+\(bu Integration of long slit spectra and 1D formats
+\(bu New \fBimred\fR packages featuring streamlined reductions
+.DE
+
+Possibly the most significant revision is the generalization allowing
+non-linear dispersion calibration.  What this means is that spectra do
+not need to be interpolated to a uniform sampling in wavelength or
+logarithmic wavelength.  The dispersion functions determined from
+calibration arc lines by \fBidentify\fR, \fBreidentify\fR,
+\fBecidentify\fR, or \fBecreidentify\fR can be simply assigned to the
+spectra and used throughout the package.  It is also possible to assign
+a dispersion table or vector giving the wavelengths at some or all of
+the pixels.  Note, however, that it is still perfectly acceptible to
+resample spectra to a uniform linear or log-linear dispersion as was
+done previously.
+.LP
+For data which does not require geometric corrections, combining, or
+separate sky subtraction the observed sampling need never be changed
+from the original detector sampling, thus avoiding any concerns over
+interpolation errors.  In other cases it is possible to just
+interpolate one spectrum, say a sky spectrum, to the dispersion of
+another spectrum, say an object spectrum, before operating on the two
+spectra.  There are several new tasks that perform interpolations to a
+common dispersion, not necessarily linear, when operating on more than
+one spectrum.  In particular, the new task \fBsarith\fR and the older
+task \fBsplot\fR now do arithmetic on spectra in wavelength space.
+Thus, one no longer need be concerned about having all spectra
+interpolated to the same sampling before doing arithmetic operations as
+was the case  previously.
+.LP
+The trade-off in using non-linear dispersion functions is a more complex
+image header structure.  This will make it difficult to import to non-IRAF
+software or to pre-V2.10 IRAF systems.  However, one may resample to a
+linear coordinate system in those cases before transfering the spectra as
+FITS images having standard linear coordinate keywords.
+.LP
+On the subject of interpolation, another important addition is the
+implementation of sinc interpolation.  This is generally considered
+the best interpolation method for spectra, however, it must be used
+with care as described below.
+Sinc interpolation approximates applying a phase shift to the fourier
+transform of the spectrum.  Thus, repeated interpolations do not accumulate
+errors (or nearly so) and, in particular, a forward and reverse
+interpolation will recover the original spectrum much more closely than
+other interpolation methods.  However, for undersampled (where the fourier
+transform is no longer completely represented), strong features, such as
+cosmic rays or narrow emission or absorption lines, the ringing can be much
+more severe than the polynomial interpolations.  The ringing is especially
+a concern because it extends a long way from the feature causing the
+ringing; 30 pixels with the truncated algorithm that has been added.  Note
+that it is not the truncation of the interpolation function which is at
+fault but the undersampling of the narrow features!
+.LP
+Because of the problems seen with sinc interpolation it should be used with
+care.  Specifically, if there are no undersampled, narrow features it is a
+good choice but when there are such features the contamination of the
+spectrum by ringing is more severe, corrupting more of the spectrum,
+than with other interpolation types.
+.LP
+The dispersion coordinates are now interfaced through the IRAF WCS
+(world coordinate system) interface.  This is important to users for
+two reasons.  First, operations performed on spectral images by IRAF
+core system tasks and the IRAF image I/O system will have access to the
+dispersion coordinates and will properly modify them as necessary.  The
+most common such operation is applying an image section to a spectrum
+either during an image copy or as input to another task.  In this case
+the relation between the pixels in the image section and their
+wavelengths is preserved.  For example one may \fBsplot\fR a section of
+a large spectrum and get the correct wavelengths.  The second reason is
+to allow use of proper dispersion coordinates in such IRAF tasks as
+\fBlistpixels\fR, \fBimplot\fR, and \fBgraph\fR.
+.LP
+The new package supports a variety of spectral image formats.  The
+older formats are understood when reading them.  In particular the one
+dimensional "onedspec" and the two dimensional "multispec" format will
+still be acceptable as input.  Note that the image naming syntax for
+the "onedspec" format using record number extensions is a separate
+issue and is still provided but only in the \fBimred.iids\fR and
+\fBimred.irs\fR packages.  Any new spectra created are either a one
+dimensional format using relatively simple keywords and a two or three
+dimensional format which treats each line of the image as a separate
+spectrum and uses a more complex world coordinate system and keywords.
+For the sake of discussion the two formats are still called "onedspec"
+and "multispec" though they are not equivalent to the earlier formats.
+.LP
+In addition, the one dimensional spectral tasks may also now operate on
+two dimensional images directly.  This is done by using the DISPAXIS
+keyword in the image header or a package dispaxis parameter if the
+keyword is missing to define the dispersion axis.  In addition there is
+a summing parameter in the packages to allow summing a number of lines
+or columns.  If the spectra are wavelength calibrated long slit
+spectra, the product of the \fBlongslit.transform\fR task, the
+wavelength information will also be properly handled.  Thus, one may
+use \fBsplot\fR or \fBspecplot\fR for plotting such data without having
+to extract them to another format.  If one wants to extract one
+dimensional spectra by summing columns or lines, as opposed to using
+the more complex \fBapextract\fR package, then one can simply use
+\fBscopy\fR (this effectively replaces \fBproto.toonedspec\fR).
+.LP
+The tasks \fBsplot\fR and \fBspecplot\fR allow use of and changes
+between various dispersion units.  Spectra may be plotted in units all
+the way from Hertz to Mev.  The units may also be inverted to plot in
+wavenumbers, such as inverse centimeters, and the decimal log may be
+applied, to plot something like log wavelength or log frequency.  One
+special "unit" which is available is a velocity computed about a
+specified wavelength/frequency.  The multiple unit capability was one
+of the last major changes made before the V2.10 release so the complete
+generalization to arbitrary units has not been completed.  Dispersion
+calibration and image world coordinate system generally must still be
+done in Angstroms, particularly if flux calibration is to be done.  The
+generalization to other units throughout the package is planned for a
+later release.
+.LP
+The last of the changes catagorized as a major highlight is the
+addition of a number of special packages for generic or specific
+types of instruments and data in the \fBimred\fR package.  Most of these
+package include a highly streamlined reduction task that combines
+all of the reduction operations into a single task.  For example,
+the \fBspectred.doslit\fR task can extract object, standard star, and
+arc spectra from long slit images, apply a consistent dispersion
+function based on only a single interactively performed dispersion
+solution, compute a sensitivity function and end up with flux
+calibrated spectra.  Another example, is \fBhydra.dohydra\fR for
+extracting, flatfielding, dispersion calibrating, and sky subtracting
+spectra from the NOAO Hydra multifiber spectrograph.  There are user's
+guides for each of these new reduction tasks.
+.NH
+Minor Highlights
+.LP
+There are some further highlights which are also quite important
+but which are secondary to the previous highlights.  These are listed
+and discussed below.
+
+.DS
+\(bu Greater use of package parameters
+\(bu An observatory database
+\(bu A more flexible \fBidentify/reidentify\fR
+\(bu Only one \fBdispcor\fR
+\(bu Spatial interpolation of dispersion solutions
+\(bu Deblending of arbitrary number of gaussian components
+\(bu Manipulating spectral formats
+\(bu Improved fitting of the continuum and related features
+\(bu Various new tasks
+.DE
+
+There is an even greater use of package parameters than in the previous
+release.  Package parameters are those which are common to many of the
+the tasks in the package and which one usually wants to change in
+one place.  The new package parameters are the default observatory for
+the data if the observatory is not identified in the image header
+(discussed further below), the interpolation type used
+when spectra need to be resampled either for dispersion calibration
+or when operating on pairs of spectra with different wavelength
+calibration, and the default dispersion axis and summing parameters
+for long slit and general 2D images (as discussed in the last section).
+You will find these parameters not only in the \fBonedspec\fR package but in
+all the spectroscopic packages in the \fBimred\fR package.
+.LP
+A number of spectroscopic tasks require information about the location
+of the observation.  Typically this is the observatory latitude for
+computing air masses if not defined in the header.  Radial velocity
+tasks, and possible future tasks, may require additional information
+such as longitude and altitude.  The difficulty is that if such
+parameters are specified in parameter files the default may well be
+inappropriate and even if the users set then once, they may forget to
+update them in later reductions of data from a different observatory.
+In other words this approach is prone to error.
+.LP
+To address this concern observatory parameters are now obtained from an
+observatory database keyed by an observatory identifier.  If the image data
+contains an observatory keyword, OBSERVAT, the tasks will look up the
+required parameters from the observatory database.  Thus, if the images
+contain the observatory identifier, as does data from the NOAO
+observatories, they will always be correctly reduced regardless of the
+setting of any parameters.  Of course one has to deal with data from
+observatories which may not include the observatory identifier and may not
+have an entry in the observatory database.  There are provisions for sites
+and individual users to define local database files and to set the default
+observatory parameters.  This is all discussed in the help for the
+\fBobservatory\fR task.
+.LP
+The dispersion function fitting tasks \fBidentify\fR and
+\fBreidentify\fR have been improved in a number of important ways.
+These tasks now treat the input images as units.  So for long slit and
+multispectrum images one can move about the image with a few
+keystrokes, transfer solutions, and so on.  When transfering solutions
+between a multispectrum reference image and another multispectrum image
+with the same apertures using \fBreidentify\fR, the features and
+dispersion solutions are transfered aperture by aperture.  This avoids
+problems encountered by having to trace successively between apertures
+and having the apertures be in the same order.
+.LP
+On the subject of tracing in \fBreidentify\fR, in some cases it is
+desirable to use the same reference spectrum with all other sampled
+lines or columns in a long slit spectrum or apertures in a
+multispectrum image rather than propagating solutions across the
+image.  The latter method is necessary if there is a continuous and
+progress shift in the features.  But if this is not the situation then
+the loss of features when tracing can be a problem.  In this case the
+alternative of reidentifying against the same starting reference is now
+possible and there will not be the problem of an increasing loss of
+features.  On the other hand, the problem of lost features, whether
+tracing or not, can also be addressed using another new feature of
+\fBreidentify\fR, the ability to add features from a line list.  For
+both tracing and nontracing reidentifications, another useful new
+feature is automatic iterative rejection of poorly fitting lines in
+determining a new dispersion function noninteractively.
+.LP
+The nontracing reidentifications, the automatic addition of new lines, and
+the iterative rejection of poorly fitting lines in determining a new
+dispersion function are all responses to make the reidentification process
+work better without intervention.  However, as a last resort there is also
+a new interactive feature of \fBreidentify\fR.  By monitoring the log output of
+the reidentification process one can have a query be made after the
+automatic reidentification and function fitting to allow selectively
+entering the interactive feature identification and dispersion function
+fitting based on the logged output.  Thus if a fit has a particularly large
+RMS or a large number of features are not found one can chose to intervene
+in the reidentification process.
+.LP
+Dispersion calibration is now done exclusively by the task
+\fBdispcor\fR regardless of the spectrum format or dispersion solution
+type; i.e. solutions from \fBidentify\fR or \fBecidentify\fR.  In addition to
+allowing assignment of non-linear dispersion functions, as described
+earlier, \fBdispcor\fR has other new features.  One is that, in
+addition to interpolating dispersion solutions between two calibration
+images (usually weighted by time), it is now possible to interpolate
+zero point shifts spatially when multiple spectra taken simultaneously
+include arc spectra.  This is mostly intended for the new generation of
+multifiber spectrographs which include some fibers assigned to an arc
+lamp source.  However, it can be used for the classic photographic case
+of calibration spectra on the same plate.
+.LP
+The limitation to four lines on the number of gaussian components which
+can be deblended by the deblending option in \fBsplot\fR has been removed.
+A new feature is that line positions may be input from a line list as 
+well as the original cursor marking or terminal input.
+In addition an option to simultaneously determine a linear background
+has been added.  As a spinoff of the deblending option a new, noninteractive
+task, called FITPROFS, has been added.  This task takes a list of initial
+line positions and sigmas and simultaneously fits gaussians with a
+linear background.  One can constrain various combination of parameters
+and output various parameters of the fitting.  While it can be used to
+fit an entire spectrum it becomes prohibitively slow beyond a number like
+30.  A banded matrix approach is required in that case.
+.LP
+As mentioned earlier there is a new task called \fBscopy\fR for manipulating
+spectra.  It allows changing between various formats such as producing
+the separate, simple keyword structure, one dimensional images from multispec
+format images, combining multiple one dimensional spectra into the
+more compact multispec format, and extracting line or column averaged one
+dimensional spectra from two dimensional images.  It can also be
+used to select any subset of apertures from a multispec format,
+merge multiple multispec format spectra, and extract regions of spectra
+by wavelength.
+.LP
+The \fBcontinuum\fR task has been revised to allow independent
+continuum fits for each aperture, order, line, or column in images
+containing multiple spectra.  Instead of being based on the
+\fBimages.fit1d\fR task it is based on the new task \fBsfit\fR.
+\fBSfit\fR allows fitting the \fBicfit\fR functions to spectra and
+outputing the results in several ways such as the ratio (continuum
+normalization), difference (continuum subtraction), and the actual
+function fit.  In addition it allows outputing the input data with
+points found to be deviant by the iterative rejection algorithm of
+\fBicfit\fR replaced by the fitted value.  This is similar to
+\fBimages.lineclean\fR.  In all cases, this is may be done
+independently and interactively or noninteractively when there are
+multiple spectra in an image.
+.LP
+A number of useful new tasks have already been mentioned:
+\fBfitprofs\fR, \fBsarith\fR, \fBscombine\fR, \fBscopy\fR, and
+\fBsfit\fR.  There are two more new tasks of interest.  The task \fBdopcor\fR
+applies doppler shifts to spectra.  It applies the shift purely to the
+dispersion coordinates by adding a redshift factor which is applied by
+the coordinate system interface.  This eliminates reinterpolation and
+preserves both the shift applied and the original observed dispersion
+function (either linear or nonlinear).  The task can also modify the
+pixel values for various relativistic and geometric factors.  This task
+is primarily useful for shifting spectra at high redshifts to the local
+rest frame.  The second new task is called \fBderedden\fR.  It applies
+corrections for interstellar reddening given some measure of the
+extinction along the line of site.
+.NH
+ONEDSPEC Package Task Reorganization
+.LP
+The \fBonedspec\fR package dates back to the earliest versions of IRAF.  Some of
+its heritage is tied to the reduction of IRS and IIDS spectra.  One of
+the revisions made for this release has been to reorganize the various
+tasks and packages.  A few tasks have been obsoleted by new tasks or
+the functionality of the new dispersion coordinate system, a number
+of new tasks have been added, and a number of IRS and IIDS specific
+tasks have been moved to the \fBimred\fR packages for those instruments.
+While these packages are organized for those particular instruments they may
+also be used by data having similar characteristics of beam switching,
+coincidence corrections, and the requirement of sequential numeric
+extensions.
+.LP
+The table below provides the road map to the reorganization showing
+tasks which have disappeared, been moved, been replaced, or are new.
+
+.DS
+.TS
+center;
+r l l l r l l.
+V2.9	V2.10	ALTERNATIVE	V2.9	V2.10	ALTERNATIVE
+
+addsets		irs/iids	process		irs/iids
+batchred		irs/iids	rebin		scopy/dispcor
+bplot	bplot		refspectra	refspectra
+bswitch		irs/iids	reidentify	reidentify
+calibrate	calibrate		sapertures
+coincor		iids	sarith
+combine		scombine	scombine
+continuum	continuum		scopy
+	deredden		sensfunc	sensfunc
+dispcor	dispcor		setdisp		hedit
+	dopcor		sextract	scopy
+	fitprofs		sfit
+flatdiv		irs/iids	sflip		scopy/imcopy [-*,*]
+flatfit		irs/iids	shedit		hedit
+identify	identify		sinterp	sinterp
+lcalib	lcalib		slist	slist
+mkspec	mkspec		specplot	specplot
+names	names		splot	splot
+	ndprep		standard	standard
+observatory		noao	subsets		irs/iids
+powercor		iids	sums		irs/iids
+.TE
+.DE
+.NH
+IMRED Packages
+.LP
+Many of the \fBonedspec\fR tasks from the previous release have been
+moved to the \fBiids\fR and \fBirs\fR packages, as indicated above,
+since they were applicable only to these and similar instruments.
+.LP
+A number of new specialized spectroscopic instrument reduction packages
+have been added to the \fBimred\fR package.  Many of these have been in
+use in somewhat earlier forms in the IRAF external package called
+\fBnewimred\fR.  In addition the other spectroscopic package have been
+updated based on the revisions to the \fBonedspec\fR and
+\fBapextract\fR packages.  Below is a table showing the changes between
+the two version and describing the purpose of the spectroscopic
+packages.  Note that while many of these package are named for and
+specialized for various NOAO instruments these packages may be applied
+fairly straightforwardly to similar instruments from other
+observatories.  In addition the same tools for multifiber and slit
+spectra are collected in a generic package called \fBspecred\fR.
+
+.DS
+.TS
+center;
+r l l s
+r l l l.
+V2.9	V2.10	SPECTROSCOPY PACKAGE
+	argus	Fiber:	CTIO Argus Reductions
+specphot	ctioslit	Slit:	CTIO Slit Instruments
+echelle	echelle	Fiber Slit:	Generic Echelle
+	hydra	Fiber:	KPNO Hydra (and Nessie) Reductions
+iids	iids	Scanner:	KPNO IIDS Reductions
+irs	irs	Scanner:	KPNO IRS Reductions
+coude	kpnocoude	Fiber/Slit:	KPNO Coude (High Res.) Reductions
+	kpnoslit	Slit:	KPNO Slit Instruments
+msred	specred	Fiber/Slit:	Generic fiber and slit reductions
+observatory	-> noao
+setairmass
+.TE
+.DE
+.LP
+An important feature of most of the spectroscopic packages are specialized
+routines for combining and streamlining the different reduction operations
+for a particular instrument or type of instrument.  These tasks are:
+
+.DS
+.TS
+center;
+r r r.
+argus.doargus	ctioslit.doslit	echelle.doecslit
+echelle.dofoe	hydra.dohydra	iids.batchred
+irs.batchred	kpnocoude.do3fiber	kpnocoude.doslit
+kpnoslit.doslit	specred.dofibers	specred.doslit
+.TE
+.DE
+.NH
+ONEDSPEC Task Revisions in V2.10
+.LS ADDSETS 2
+Moved to the \fBiids/irs\fR packages.
+.LS BATCHRED
+Moved to the \fBiids/irs\fR packages.
+.LS BPLOT
+The APERTURES and BAND parameters been added to select 
+apertures from multiple spectra and long slit images, and bands
+from 3D images. Since the task is a script calling \fBsplot\fR, the
+many revisions to that task also apply. The version in the
+\fBiids/irs\fR packages selects spectra using the record number 
+extension syntax.
+.LS BSWITCH
+Moved to the \fBiids/irs\fR packages.
+.LS CALIBRATE
+This task was revised to operate on nonlinear dispersion 
+corrected spectra and 3D images (the \fBapextract\fR "extras"). The
+aperture selection parameter was eliminated (since the header
+structure does not allow mixing calibrated and uncalibrated
+spectra) and the latitude parameter was replaced by  the 
+observatory parameter. The observatory mechanism insures that
+if the observatory latitude is needed for computing an airmass
+and the observatory is specified in the image header the
+correct calibration will be applied. The record format syntax
+is available in the \fBiids/irs\fR packages. The output spectra are
+coerced to have real pixel datatype.
+.LS COINCOR
+Moved to the \fBiids\fR package.
+.LS COMBINE
+Replaced by \fBscombine\fR.
+.LS CONTINUUM
+This task was changed from a script based on \fBimages.fit1d\fR to a
+script based on \fBsfit\fR. This provides for individual independent
+continuum fitting in multiple spectra images and for additional
+flexibility and record keeping.  The parameters have been 
+largely changed.
+.LS DEREDDEN
+This task is new.
+.LS DISPCOR
+This is a new version with many differences. It replaces the
+previous three tasks \fBdispcor\fR, \fBecdispcor\fR and \fBmsdispcor\fR. It
+applies both one dimensional and echelle dispersion functions.
+The new parameter LINEARIZE selects whether to interpolate the
+spectra to a uniform linear dispersion (the only  option 
+available previously) or to assign a nonlinear dispersion 
+function to the image  without  any  interpolation.  The 
+interpolation function parameter has been eliminated and the
+package parameter INTERP is used to select the interpolation
+function. The new interpolation type "sinc" may be used but
+care should be exercised. The new task supports applying a
+secondary zero point shift spectrum to a master dispersion
+function and a spatial interpolation of the shifts  when 
+calibration spectra are taken at the same time on a different
+region of the same 2D image. The optional wavelength table may
+now also be an image to match dispersion parameters. The
+APERTURES and REBIN parameters have been eliminated.  If an
+input spectrum has been previously dispersion corrected it will
+be resampled as desired. Verbose and log file parameters have
+been added to log the dispersion operations as desired. The
+record format syntax is available in the \fBiids/irs\fR packages.
+.LS DOPCOR
+This task is new.
+.LS FITPROFS
+This task is new.
+.LS FLATDIV
+Moved to the \fBiids/irs\fR packages.
+.LS FLATFIT
+Moved to the \fBiids/irs\fR packages.
+.LS IDENTIFY
+The principle revision is to allow multiple aperture images and
+long slit spectra to be treated as a unit. New keystrokes
+allow jumping or scrolling within multiple spectra in a single
+image. For  aperture  spectra  the database entries are 
+referenced by image name and aperture number and not with image
+sections. Thus, \fBidentify\fR solutions are not tied to specific
+image lines in this case. There is a new autowrite parameter
+which may be set to eliminate the save to database query upon
+exiting. The new colon command "add" may be used to add
+features based on some other spectrum or arc type and then
+apply the fit to the combined set of features.
+.LS LCALIB
+This task has a more compact listing for the "stars" option and
+allows paging a list of stars when the star name query is not
+recognized.
+.LS MKSPEC
+This task is unchanged.
+.LS NAMES
+This task is unchanged.
+.LS NDPREP
+This task was moved from the \fBproto\fR package. It was originally
+written at CTIO for CTIO data. It's functionality is largely
+unchanged though it has been updated for changes in the 
+\fBonedspec\fR package.
+.LS OBSERVATORY
+New version of this task moved to \fBnoao\fR root package.
+.LS POWERCOR
+Moved to the \fBiids\fR package.
+.LS PROCESS
+Moved to the \fBiids/irs\fR package.
+.LS REBIN
+This task has been eliminated. Use \fBscopy\fR or \fBdispcor\fR.
+.LS REFSPECTRA
+A group parameter was added to allow restricting assignments by
+observing period; for example by night.  The record format
+option was removed and the record format syntax is available in
+the \fBiids/irs\fR packages.
+.LS REIDENTIFY
+This task is a new version with many new features.  The new
+features include  an  interactive  options  for reviewing 
+identifications, iterative rejection  of  features  during 
+fitting, automatic addition of new features from a line list,
+and the choice of tracing or using a single master reference
+when reidentifying features in other vectors of a reference
+spectrum. Reidentifications from a reference image to another
+image is done by matching apertures rather than tracing. New
+apertures not present in the reference image may be added.
+.LS SAPERTURES
+This task is new.
+.LS SARITH
+This task is new.
+.LS SCOMBINE
+This task is new.
+.LS SCOPY
+This task is new.
+.LS SENSFUNC
+The latitude parameter has been replaced by the observatory
+parameter. The 'i' flux calibrated graph type now shows flux
+in linear scaling while the new graph type 'l' shows flux in
+log scaling. A new colon command allows fixing the flux limits
+for the flux calibrated graphs.
+.LS SETDISP
+This task has been eliminated.  Use \fBhedit\fR or the package
+DISPAXIS parameter.
+.LS SEXTRACT
+Replaced by \fBscopy\fR.
+.LS SFIT
+This task is new.
+.LS SFLIP
+This task has been eliminated. Use image sections.
+.LS SHEDIT
+This task has been eliminated. Use \fBhedit\fR if needed.
+.LS SINTERP
+This task is unchanged.
+.LS SLIST
+This task was revised to be relevant for the current spectral
+image formats. The old version is still available in the
+\fBiids/irs\fR package.
+.LS SPECPLOT
+New parameters were added to select apertures and bands, plot
+additional dimensions (for example the additional output from
+the extras option in \fBapextract\fR), suppress the system ID banner,
+suppress the Y axis scale, output a logfile, and specify the
+plotting units.  The PTYPE parameter now allows negative 
+numbers to select histogram style lines.  Interactively, the
+plotting units may be changed and the 'v' key allows setting a
+velocity scale zero point with the cursor.  The new version
+supports the new spectral WCS features including nonlinear
+dispersion functions.
+.LS SPLOT
+This is a new version with a significant number of changes. In
+addition to the task changes the other general changes to the
+spectroscopy packages also apply. In particular, long slit
+spectra and spectra with nonlinear dispersion functions may be
+used with this task. The image header or package dispaxis and
+nsum parameters allow automatically extracting spectra from 2D
+image. The task parameters have been modified primarily to
+obtain the desired initial graph without needing to do it
+interactively. In particular, the new band parameter selects
+the band in 3D images, the units parameter selects the 
+dispersion units, and the new histogram, nosysid, and xydraw
+options select histogram line type, whether to include a system
+ID banner, and allow editing a spectrum using  different 
+endpoint criteria.
+.LS
+Because nearly every key is used there has been some shuffling,
+consolidating, or elimination of keys. One needs to check the
+run time '?' help or the help to determine the key changes.
+.LS
+Deblending may  now  use  any  number of components and 
+simultaneous fitting of a linear background. A new simplified
+version of gaussian fitting for a single line has been added in
+the 'k' key. The old 'k', 'h', and 'v' equivalent width
+commands are all part of the single 'h' command using a second
+key to select a specific option. The gaussian line model from
+these modes may now be subtracted from the spectrum in the same
+way as the gaussian fitting.  The one-sided options,  in 
+particular, are interesting in this regard as a new capability.
+.LS
+The arithmetic functions between two spectra are now done in
+wavelength with resampling to a  common  dispersion  done 
+automatically. The 't' key now provides for the full power of
+the ICFIT package to be used on a spectrum for continuum
+normalization, subtraction, or line and cosmic ray removal.
+The 'x' editing key may now use the nearest pixel values rather
+than only the y cursor position to replace regions by straight
+line segments. The mode is selected by the task option 
+parameter "xydraw".
+.LS
+Control over the graph window (plotting limits) is better
+integrated so that redrawing, zooming, shifting, and the \fBgtools\fR
+window commands all work well together. The new 'c' key resets
+the window to the full spectrum allowing the 'r' redraw key to
+redraw the current window to clean up overplots from the
+gaussian fits or spectrum editing.
+.LS
+The dispersion units may now be selected and changed to be from
+hertz to Mev and the log or inverse (for wave numbers) of units
+taken. As part of the units package the 'v' key or colon
+commands may be used to plot in velocity relative to some
+origin. The $ key now easily toggles between the dispersion
+units (whatever they may be) and pixels coordinates.
+.LS
+Selection of spectra has become more complex with multiaperture
+and long slit spectra. New keys allow selecting apertures,
+lines, columns, and bands as well as quickly scrolling through
+the lines in multiaperture spectra. Overplotting is also more
+general and consistent with other tasks by using the 'o' key to
+toggle the next plot to be overplotted. Overplots, including
+those of the gaussian line models, are now done in a different
+line type.
+.LS
+There are new colon commands to change the dispersion axis and
+summing parameters for 2D image, to toggle logging, and also to
+put comments into the log file.
+.LS STANDARD
+Giving an unrecognized standard star name will page a list of
+standard stars available in the calibration directory and then
+repeat the query.
+.LS SUBSETS
+Moved to the \fBiids/irs\fR packages.
+.LS SUMS
+Moved to the \fBiids/irs\fR packages.