What is IRAF?

    IRAF is the Image Reduction and Analysis Facility, a general purpose
software system for the reduction and analysis of scientific data.  IRAF is
written and supported by the IRAF programming group at the National Optical
Astronomy Observatories (NOAO) in Tucson, Arizona.  IRAF includes a good
selection of programs for general image processing and graphics
applications, plus a large number of programs for the reduction and analysis
of optical astronomy data within the NOAO package.  A number of external or
layered packages are available including packages for the analysis of HST,
XRAY and EUV data.  Users can add their own software to IRAF.  IRAF provides
a complete programming environment including a Command Language scripting
facility, the IMFORT Fortran programming interface, and the full native
SPP/VOS programming environment in which the portable IRAF system is
written.

Further information on IRAF can be found in the IRAF FAQ (frequently asked
questions list) available in the IRAF archives.