IRAF is the Image Reduction and Analysis Facility, a general purpose software system for the reduction and analysis of astronomical data. IRAF is licensed under a MIT style license. The software was written by the National Optical Astronomy Observatories (NOAO) in Tucson, Arizona. However, development and maintenance of IRAF is discontinued since 2013. The latest NOAO release had a large number of problems, including major license issues and security bugs.
To prevent the software from bitrotting, and to fix bugs that are in the package despite (or because) of its age, the iraf-community works on maintaining IRAF and integrating the available patches into the source code.
Please be aware the IRAF is 35 years old legacy code and institutional support for IRAF and its usage is going away quickly. It is recommended to search alternative solutions, for example in the Astropy community, and not to start new projects using IRAF. See this article in the STScI newsletter for rationale and recommendations.
Contributing Code, Documentation, or Feedback
IRAF can only survive by the contribution of its users, so we welcome and encourage your contributions. The preferred way to report a bug is to create a new issue on the IRAF GitHub issue page. To contribute patches, we suggest to create a pull request on GitHub. Another way to contribute is to package IRAF for your favourite operating system and distribution.
IRAF is listed in the Astronomical Source Code Library as ascl:9911.002. There are two papers appropriate as references for IRAF in a publication: