IRAF

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IRAF

IRAF

Developer:	NOAO
Stable release	2.14 (14 January 2008)
OS:	Cross-platform
Genre:	Astronomical Analysis
Website:	http://iraf.noao.edu

IRAF (an acronym for Image Reduction and Analysis Facility) is a huge collection of software written by astronomers and by programmers at the National Optical Astronomy Observatory (NOAO) geared towards the reduction of astronomical images in pixel array form, that is, data taken from imaging array detectors such as CCDs. It is available for all major operating systems for mainframes and desktop computers. Although written for UNIX-like operating systems, use on Microsoft Windows is made possible by Cygwin. It is primarily used on Linux distributions, with a growing share of Mac OS X users.

IRAF commands (known as tasks) are organized into package structures. Additional packages may be added to IRAF. Packages may contain other packages. There are many packages available by NOAO and external developers often focusing on a particular branch of research or facility. Of particular note are the STSDAS and TABLES packages by the STScI.

The licensing status of IRAF is conflicted but generally follows the MIT license scheme, with some older parts of the code under a different license. Most notably, several functions in the graphics infrastructure are under a non-free software license which does not permit redistribution without permission. As this code is tightly integrated into a few tasks IRAF, the package as a whole is seen by several projects as non-redistributable and therefore non-free. NOAO seems to have made no effort to clarify this situation, open-source developers concerned with license issues have made no effort to correct this on their own, and so efforts to package the software for drop-in installation in GNU/Linux systems have lapsed.^[1]

[edit] Technical details

A full IRAF working environment usually requires two other applications: an extended xterm window with a graphics windows (called xgterm and distributed in a separate X11IRAF package by NOAO) and an image display program referred to as an "image server". The two most popular image servers are ds9 (by SAO) and ximtool (NOAO). The ximtool display server currently only supports 8-color displays but a new version is in the works.