This environment is being replaced by a Ureka-based installation. Please see for more information.

IRAFX (despite the name) represents the recent development versions of STScI STSDAS, a software package for reducing and analyzing astronomical data and routines specifically designed for HST data, and stsci_python, our Python-based software including tools such as pyfits, pyraf, and multidrizzle. Improvements to HST pipelines and STSDAS tasks are always made first in IRAFX, before being released later to the community as part of STScI's standard IRAF release (roughly twice a year). Users who rely on such improvements and who wish to have access to the latest versions of all the software, may want to consider using IRAFX.

IRAFX is the software that the Science Software Branch is developing. Users who want to use IRAFX should be aware that, even if the software is presumed to be fairly reliable, it has not been fully tested. It may occasionally malfunction.

Users should also be aware that there is no support for this version of the software; however, we would like to hear about any problems with IRAFX. Please, report any issue to

The new version of IRAFX appears on our website each Monday, though we occasionally skip a week. Check the time stamp next to the download link.


Documentation for irafx is available on our download server.

Mailing list

There is a mailing list where we occasionally make announcements about IRAFX. You may also use this mailing list to discuss the features under development. Use this form to subscribe:

For Macintosh

IRAFX is installable as a Macintosh package. To use it:

This DMG is not compatible with Scisoft. You must choose whether to initialize your environment for Scisoft or for these packages. It is not practical to switch from one to the other -- you must change your login scripts and start a new terminal window.

For Linux or Macintosh

If you are installing this software on a Linux machine or you do not want to use the entire IRAF/Python environment in the Mac DMG, use these instructions:

This software is distributed in two parts:


stsci_python_irafx.tar.gz ( updated Mon 2013-12-16 00:33:54 ) - Weekly stsci_python, as source code. This requires Python 2.6 or 2.7.

To use it, use the "Installing from Source" instructions here


hstcal_x.tar.gz ( updated Mon 2013-12-16 00:33:54 ) - Weekly hstcal, as source code.

The tar file contains a directory named hstcal_x. To install it, see file INSTALL.


Download one of these: To install, extract the tar file. You will find a directory named stsci_irafx. cd to that directory and run the script


It will tell you the lines to put in extern.pkg so that IRAF can find the tasks.