Welcome to the HSTaXe package documentation!

HSTaXe is a Python package to provide a uniform process to perform spectral extraction for the Hubble Space Telescope. HSTaXe supports all slitless spectroscopy modes provided by the Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS).

The core hstaxe is written in ANSI C and is highly cross-platform by leveraging CFITSIO, GSL, and WCSLIB, which have been successfully employed under Linux, Solaris, and MacOS X.

HSTaXe is the successor to aXe, a similar package written on PyRAF/IRAF.


This documentation mostly overlaps with, but is not identical to, the original aXe manual. This means that many of the descriptions and code snippets provided refer to the old command line/IRAF-based version of aXe rather than the current python-based hstaxe. The installation and example notebooks sections, as well as some content related to background subtraction, has been more recently updated to be up-to-date for hstaxe. The rest of the older content is nonetheless useful for understanding what is going on “under the hood”.

The last version of the aXe manual can be downloaded from the hstaxe repository.


This software was originally developed by the ACS group of the Space Telescope - European Coordinating Facility (ST-ECF). The ST-ECF is a department jointly run by the European Space Agency and the European Southern Observatory. It is located at the ESO headquarters at Garching near Munich. The ST-ECF staff supports the European astronomical community in exploiting the research opportunities provided by the earth-orbiting Hubble Space Telescope.

STECF supported the use of the aXe software and the slitless spectroscopic modes of ACS and WFC3 until late 2010. Since the beginning of 2011 support has been provided by STScI. Please send questions to: http://hsthelp.stsci.edu


Norbert Pirzkal (ST-ECF/STScI), Markus Demleitner (ST-ECF), Martin Kuemmel (ST-ECF), Richard Hook (ST-ECF/STScI), Howard Bushouse (STScI), Megan Sosey (STScI), Ricky O’Steen (STScI), Duy Nguyen (STScI)

Using HSTaXe