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,

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:

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:

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:

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:


CTOOLS


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:

The following bugs were fixed:

MultiDrizzle 3.1

The following changes were made:

The following bugs were fixed:


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.