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STSDAS Version 3.8 Release Notes

  11 February 2008

This release of STSDAS contains changes to NICMOS, ACS, STIS, WFPC/CALWP2, Dither, SYNPHOT, Nebular, and CTOOLS, with some minor changes to GFLIB.

One new package has been added; namely,
  • WFC3: This package currently only contains CALWF3, the pipeline processing software for WFC3 data. 

The specific changes are detailed in the following sections.

Platform Support

Binaries for this release were built on Red Hat Enterprise Linux 3, Solaris 5.8, and Mac OS X 10.4 (PPC and Intel architecture).
Binaries were built with IRAF 2.14, except for Solaris, which were built with IRAF 2.12.2a.  IRAF is available from http://iraf.net.

HST_CALIB

CALACS 4.6.5

CALACS was updated to Version 4.6.5 (18-Jan-2008) in order to implement support for time-dependent sensitivity as reported by the photometry keywords in the ACS image headers.  The time-dependent changes to the DQE are recorded in the SYNPHOT throughput tables and are now used by CALACS to compute more accurate photometry keyword values.  This version also fixed a bug caused by spurious negative pixels showing up in raw SBC data.

AXE

AXE remains stable at version 1.6. See the official aXe site for details related to this task.

NICMOS

This release contains CALNICA Version 4.2. The major changes in this version improve performance in a multi-accum exposure by using up-the-ramp fitting with optimal weighting to determine the integrated flux (countrate) for each pixel, and by rejecting cosmic rays more accurately. Changes were also made to include the Poisson noise contribution in the error estimate,  correctly calculate integration time, and flag pixels showing evidence of curvature in the detector response. The NICMOS team will be issuing an Instrument Science Report that describes these changes in more detail.

Other bug fixes included in the release:
  • rnlincor: handling of the sky values corrected 
  • saaclean: version numbers no longer printed out
  • Both rnlincor and saaclean were written in python and they are only available under PyRAF.
  • calnica now exits if the _spt file is not found (previously silently used a temperature of 0.0 in the temperature-dependent dark correction)

STIS

This release contains CALSTIS Version 2.26 (04-October-2007) and represents the calibration to be used for the final reprocessing of all STIS data taken prior to SM4. 

The following bugs were corrected:
  • CALSTIS would occasionally crash on imaging data, due to a problem in the IRAF FITS kernel when the number of header keywords was close to a multiple of 36.   Three dummy keywords are now added to DQ headers to work around this problem.
  • Problems seen when running CALSTIS on Macs caused by not correctly binning the bad pixel table values for binned STIS images was corrected.

WFPC2

CALWP2 has been updated to Version 2.4.3 (Feb 4, 2008) in this release. 

This version implements the new zero-point keywords to provide the photometric correction based on calibrations of the contamination.

This version also corrected the following bugs:
  • Some behaviors of the WF4T correction as originally implemented were corrected to work even when many of the calibration steps (in particular, BLEVCORR) were turned off.
  • CALWP2 will no longer crash if the WF4TCORR keyword is set to PERFORM yet no reference file was specified.

In addition, the help file for the CRREJ task was updated to reflect errors produced under IRAF v2.14 when the input image has pixel type of SHORT.

Synphot

There are no changes to the Synphot software in this release.
    Data changes:

  • Improved wavelength tables were provided for COS based on improved dispersion coefficients from the IDT.
  • The detectors.dat table was updated to include WFC3 parameters.

CTOOLS

  • specalign: An array allocation error in the specalign task was fixed. A temporary array for the wavelength shifts was allocated with an array size equal to the length of a spectrum, but the array size should have been the number of spectra.  This failed when the number of spectra was large.
  • chcalpar: Parameter sets were updated to include the new SAACORR and WF4TCORR calibration switches for NICMOS and WFPC2 data, respectively.

ANALYSIS

Drizzle

Fixed a bug in the computation of the weight values for pixels when images get flipped.

PyDrizzle 6.1

The following changes were made to improve support for WFPC2 data:
  • DQ information for WFPC2 data now correctly recognized for all input formats
  • PyDrizzle creates an empty DQ array for use by PyDrizzle if none are found.

The following bugs were fixed:
  • Processing an image which does not have any distortion coefficients now works as expected; specifically, no changes get imposed on the image.
  • Corrected a problem in the definition of the default DQ array

MultiDrizzle 3.1

The following changes were made:
  • The default behavior for multidrizzle when run from STSDAS will be to NOT create the context image for the output product.
  •  Automatic generation of IVM files for use with NICMOS data has been added.
  • Error states now generate exceptions with error messages more directly related to the cause of the problem.
  • Now updates WFPC2 DQ image (c1h files as converted to FITS format) with cosmic-ray mask identifications made by MultiDrizzle. If no c1h files are present on input, the cosmic-ray identifications do not get reported to the user.
  • Simplified the creation of a NICMOS dark image for use in IVM generation.  Multidrizzle assumes a constant dark rate for the detectors.

The following bugs were fixed:
  • Fixed a bug in how the output name gets determined for a single input image.
  • Fixed a bug in the handling of flat field images in the NICMOS IVM generation routines.  Multidrizzle now uses NICMOS flats are properly gain corrected.
  • The algorithm for creating the IVM files automatically was corrected.
  • Removed all remaining references to use of older cubic distortion coefficients for WFPC2 data, replacing them with references to IDCTAB reference file.
  • Fixed a problem with the error messages generated when the boxcar convolution in the minmed algorithm fails.


New support for using MultiDrizzle with WFPC2 data can also be found online at http://www.stsci.edu/hst/wfpc2/analysis/drizzle.html .

Nebular

This patch updates atomic data and help file in the analysis.nebular package of STSDAS V3.8 (scheduled for early 2008). Versions of nebular in later releases of STSDAS do not  require the application of this patch. The details of the updates and the effects on abundance calculations are described in the README file delivered with the package.


ZZSETENV.DEF

Some changes have been made to the zzsetenv file to improve the installation procedure when installing multiple versions of IRAF on a single system, and to avoid overriding already-set environment variables for synphot-related variables.

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