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Space Telescope Imaging Spectrograph
Additions/updates to tasks STIS package

Additions/updates to STIS package tasks in STSDAS v3.1

A new python task has been introduced in the STIS package:

stisnoise - This is a task written in python for measuring and removing coherent electronic read noise in STIS images. See STIS ISR 2001-05 for a description of the algorithm. This task runs either within the Pyraf environment, or as a stand-alone python task (i.e., it doesn't run in the standard IRAF CL setup).

Four tasks in the STIS package have undergone improvements and are listed below:

doppinfo - This task computes and prints out Doppler shift information for each imset of a STIS dataset. It does not modify the input dataset or any of its keyword values.

tastis - The criteria used to define whether or not an acquisition was successful have been slightly modified, and should now give fewer spurious warning messages. Also, setting "update=yes" will now add several keywords to the header of the acquisition dataset indicating whether or not the acquisition passed the screening tests done by the procedure.

odelaytime - This task corrects event times in time-tag data to the solar system barycenter, (i.e., it corrects for variable light travel time delays). Now it also corrects the EXPSTART, EXPEND, TEXPSTRT, AND TEXPEND keywords in each extension of ACCUM files for these time delays. This task can now also handle the case where an observation spans the boundary between two ephemeris files.

inttag - The FITS standard now specifies different keywords for images and tables for mapping between pixel coordinates and "world" coordinates (such as right ascension and declination), and it prohibits the presence of image-type keywords in a table header or table-type keywords in an image header. inttag was modified to conform to this standard.