We have released CALSTIS version 2.3. Pipeline processing will use this version shortly, and is is included in the recent release of STSDAS 2.1. Changes to CALSTIS in this version include a number of bug fixes, enhancements, and a number of new user tools and scripts.

The following OPRs are closed by the release of CALSTIS 2.3:

OPR 37635:  CALSTIS8 is confused about number of imsets
OPR 37810:  Calstis should use XTRACALG from first matching 
            row in XTRACTAB
OPR 37980:  STIS NUV dark should be scaled according to 
            temperature
OPR 38257:  Add debug option to calstis4
OPR 38258:  Calstis4 should read parameters from a table
OPR 38749:  Calstis6 should check for zero aperture throughput
OPR 38751:  Discontinuity in STIS 2-D interpolation
OPR 38762:  Revise 1-D interpolation for CALSTIS
OPR 39281:  Function name conflict between CALSTIS and HSTIO
OPR 39282:  CALSTIS should not use global variable STATUS
OPR 39316:  CALSTIS should reset cosmic ray flags read from 
            input images
OPR 39687:  STIS 1-D interpolation bug
OPR 39688:  CALSTIS2 calling sequence error (niter)
OPR 39716:  Change background clipping in STIS 1-D extraction
OPR 39780:  CALSTIS should check for zero exposure time (TEXPTIME)

NUV Dark Scaled by MAMA Temperature

This enhancement was attempted in CALSTIS 2.0, but that release was taking the MAMA temperature from the wrong location. This is still not a perfect solution as the NUV background depends in a complex way on the current temperature as well as the temperature history.

CALSTIS 4 Now Reads Wavelength Calibration Parameters from a Reference File

Several parameters used in processing STIS wavelength calibrations were moved from inside the source code to a new reference file to enhance our ability to change them.

CALSTIS 6 Now Checks Reference Files for Zero Throughput

The flux-calibration section of CALSTIS 6 would generate divide-by-zero errors in certain instrument configurations as the throughput is zero in some wavelength regions. Since the flux calibration is essentially undefined in these regions, divide by zeroes are now tested for and avoided.

Discontinuities in STIS 2-D Interpolation Fixed

The 2-D interpolation scheme used in CALSTIS 7 would occasionally generate flux discontinuities in the calibrated data. This has been fixed.

CALSTIS2 Reset the Cosmic Ray Flags Read from Input Images

If calstis2 is run twice in succession, the cosmic-ray bit (8192) is set in the input data quality (DQ) extensions on the first run, and then those DQ values are copied to the output DQ extension on the second run. Calstis2 was modified to clear the cosmic-ray bit as it reads the DQ values from the input imsets.

Change the Background Clipping Algorithm for STIS 1-D Extraction

In the 1-D extraction step of calstis, there are cases where almost all the output points are flagged as having too many background pixels rejected (2048), largely pixels with no counts. This was changed so that pixels with zero counts are no longer treated as outliers.

CALSTIS Now Checks for Zero Exposure Time

Some data obtained with zero exposure time (e.g., when the take data flag went down due to a GS acquisition failure) would cause the pipeline to bomb due to a divide by zero. This condition is now tested for and avoided.

Updated User Tasks and New User Tasks in CALSTIS 2.3:

DAYDARK Task Updated

The main changes are as follows:

1. daydark now accepts an input file template (i.e., a list of input files, or wildcards) instead of a single input file name;
2. it now allows for CALSTIS processing of raw input dark files before updating the hot pixels. This is necessary to create proper daily dark files for data taken after June 29, 1998. Full details on the use of the new "daydark" task are available through the STIS web pages.

Fringe Flat Tasks Updated

The tasks related to fringe correction for G750L and G750M spectra (normspflat, prepspec, mkfringeflat, and defringe) have been updated in order to ensure compatibility with the current IRAF FITS kernel.

ovac2air.cl

This is a new task which corrects the wavelengths in a 1-D extracted spectrum from vacuum to air, if the vacuum wavelength is longer than 2000 Angstroms.

sdqflags.cl

This is a new task to aid in setting the SDQFLAGS keyword in SCI extension headers. The parameters are descriptive names of the data quality conditions rather than their numerical values, and the task prints the sum of the numerical values for the selected conditions. The sum can be used for the SDQFLAGS keyword.

wavecal.cl (and _cs4.cl)

A new parameter 'debugfile' has been added. If the value is not null, a file with that name will be created (or appended to), and extensive information for testing or debugging will be printed to that file.

x1d.cl

Many of the task parameters were renamed to make them consistent with the columns in the 1-D extraction table (XTRACTAB). A new parameter 'globalx' was added to give the option of using the average of the cross correlation offsets for all orders; this is useful for echelle data if the signal level is weak enough that many orders will be virtually blank.