The Science Software Branch at STScI

The Science Software Branch at STScI is part of the Engineering and Software Services (ESS) division. The primary function of the Branch is to develop, code, test and maintain science software, principally in the area of Data Analysis. We are responsible for a number of STScI data analysis products:


General purpose data analysis tools that run under the IRAF environment, including HST instrument calibration pipelines.

Related Sites:

STScI home
ESS Home Page
HST Instruments
Old STSDAS page
Old PyRAF page
Old PyFITS page
Old numarray page
Internal SSB page
TABLES The TABLES package allows manipulation of STSDAS-format tables, and is REQUIRED in order to run STSDAS.
PyRAF is an alternative environment to the IRAF cl for running IRAF/STSDAS tasks: it provides access to almost all of IRAF/STSDAS functionality, but with the added power and flexibility of the Python scripting language.
PyFITS is a module that, when combined with the numarray package, allows Python users to access the data and headers of FITS files.
numarray is a package that allows fast manipulation of arrays in python, in a way that is similar to the capabilites of IDL.
SpecView is a spectrum plotting/visualization tool written in Java.
PyDrizzle is a Python package that simplifies the combination of dithered images. It is a wrapper around the "drizzle" program of Fruchter and Hook.
HST exposure time calculators
CGI exposure time calculators for ACS, NICMOS and STIS.

Users can get help on any of these products by sending mail to, including information about the task/package that is causing the problem, the type of computer and operating system, and the version of the software being used. Alternatively, you can call (410) 338-1082 or 1-800-544-8125

Copyright Notice Last updated: 3 March 2003