Section 1: GENERAL

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.  External or layered packages are
also available for the analysis of HST, XRAY and EUV data.  IRAF provides
a complete programming environment, which includes the Command Language
script facility, the IMFORT Fortran programming interface, and the fully
featured SPP/VOS programming environment in which the portable IRAF system
is written.

Should I get it - is it appropriate for my needs?

 There are basically three reasons to get IRAF:
	The first one is that you have astronomical data that needs to be
processed and you are looking for a mature, Unix-, PC-, or VMS-based, image
processing system to do the work.
	The second reason is that you would like to develop some astronomical
software and are looking for a popular astronomical software package - one
with a broad selection of tools - to build on to lessen your work.  IRAF
provides the software developer with a rich programming environment that
includes file management tools, interactive graphics and display, portability,
and much MUCH more.
	The third reason to acquire IRAF is to process data that is similar
to astronomical data, and the basic interactive graphics, display tools,
and image operators provided by IRAF would be useful for your application.

What general image processing tools are included with the core system?

 The IRAF core system is the basic IRAF system and does not include the
suite of reduction packages known as the NOAO package.  (But note that
the NOAO package is included in all IRAF distributions.)  The IRAF core
system provides tools for reading and writing data in the transportable
FITS format (although other i/o tools are available), interactive graphics
and image display tools for examining your data, tools for image registration
and cleaning bad pixels, a variety of smoothing operators, and tools for
image arithmetic, image statistics and combining image frames.

What software does IRAF have for spectral data?

 IRAF has a rich selection of tools for spectral reduction and analysis in
the NOAO package that spans 1-d, 2-d, echelle, and fibor spectroscopy.  These
tools include basic CCD reductions and flat fielding, distortion corrections
for 2-d data, extraction of 2-d and echelle frames, wavelength and flux
calibration, radial velocity analysis, and a multitude of tasks for
manipulating spectra in general.  The tasks provide the user with the
option of batch or interactive processing.

What software does IRAF have for direct imaging data?

 Besides the image operators provided by the basic core system (see earlier
FAQ) the NOAO package in IRAF provides tools for basic CCD reductions,
mosaicing, aperture and PSF-fitting (DAOPHOT) photometry, and photometric
calibration.  A package for surface photometry is planned and will be added
at a later date.

Are the IRAF reduction packages limited to use with NOAO instruments?

 The many reduction packages within the IRAF system are not limited to
use with NOAO instruments.  The tasks within IRAF have been developed to
be as generic as possible to encompass a wide range of uses.

How do I get IRAF; how much does it cost?

 IRAF is available free of charge over the network.  Use anonymous FTP to
connect to node ( and "get README".  Each level
of the archive has a README file to assist you with your selections or with
your transfers.  
If acquiring IRAF over the network is not an option for you (but we do prefer
you retrieve it that way) then an orderform is available.
A small recovery fee is charged for mailed
distributions along with any shipping and handling fees.  Typical orders in the
US run about $58 (US), and foreign shipments run between $100-$250 (when
documentation is included).

Is IRAF public domain software?

 Although IRAF is available free of charge over the network to anyone who
may find it useful it is not considered public domain software since it is
copyrighted.  Here is part of the copyright notice that appears in the
distributed system.
Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
The IRAF software is publicly available, but is NOT in the public domain.
The difference is that copyrights granting rights for unrestricted use and
redistribution have been placed on all of the software to identify its authors.
You are allowed and encouraged to take this software and use it as you wish,
subject to the restrictions outlined below.
Permission to use, copy, modify, and distribute this software and its
documentation is hereby granted without fee, provided that the above copyright
notice appear in all copies and that both that copyright notice and this
permission notice appear in supporting documentation, and that references to
the Association of Universities for Research in Astronomy Inc. (AURA),
the National Optical Astronomy Observatories (NOAO), or the Image Reduction
and Analysis Facility (IRAF) not be used in advertising or publicity
pertaining to distribution of the software without specific, written prior
permission from NOAO.  NOAO makes no representations about the suitability
of this software for any purpose.  It is provided "as is" without express or
implied warranty.

What are the system requirements if I want to install IRAF?

 For a typical, single-user, workstation environment you will need a
minimum of 64Mb of memory and ~128Mb of swap space.  You will need about
128 of diskspace for the IRAF system (this varies a bit with the platform), although it can be stripped to about half that after the installation.  If
you are configuring a server your memory and swap space needs will be more
(maybe much more!).  

What is the current version of IRAF?

 The current version of IRAF varies a bit with the platform.
    --------              ---------------       ------------
    AIX4                  V2.11.3               15 December 1999
    DUNX                  V2.11.3               15 December 1999
    HPUX                  V2.11.3               15 December 1999
    IRIX                  V2.11.3               15 December 1999
    PCIX                  V2.11.3                7 December 1999
    SSOL                  V2.11.3                7 December 1999
    VMS7                  V2.11.3               15 December 1999

When is the next version of IRAF going to be released?

	It is always difficult for us to predict exact release dates,
so the best thing to do is check the archive ( occasionally
for new distributions.

What is the status of XGterm and XImtool?

 The X11IRAF project is being developed independently of the normal IRAF
system development.  They are X based tools for support of vector graphics
and image display, the long awaited replacements for Xterm and SAOimage.
Versions of XGterm, XImtool and XTapemon are available in the /iraf/x11iraf
directory on   A new version was recently made available that
contains many enhancements, especially to ximtool (e.g. hardcopy capability,
image load/save, on-line help, etc).  All tasks are now fully documented
and easily buildable from source on all supported iraf platforms.  A bug-fix
release was made available in Aug 97, most users should upgrade to this
version.  Another version to support the prototype science GUIs (XAPPHOT,
SPECTOOL, and XRV) is planned for the near future that will also include
many bug fixes and necessary system enhancements (contact site support for

On which platforms does IRAF run?

 IRAF runs on the following platforms:
        Platform		Descrition
	AIX4			IBM/RS6000 AIX 4.x
	DUNX			Digital Unix 4.0 (OSF, Compaq Tru64)
	HPUX			HP-UX 10.20
	PCIX			FreeBSD 3.3
	PCIX			Slackware Linux 4.0
	PCIX			RedHat Linux 5.x
	PCIX			RedHat Linux 6.x
	PCIX			SuSE Linux 6.x
	PCIX			Solaris 7 for Intel
	SSOL			SunOS 4.x
	SSOL			Solaris 5.5, 5.6, 5.7, 5.8
	VMS7			VAX/VMS 7.1

Does IRAF run on a PC under DOS? under Unix?

 The V2.11 IRAF system for PCs running Linux/FreeBSD is now
available from the archives or on the V2.11 CD-ROM by filling
out the IRAF orderform.  No port is planned
for DOS/Windows 95/98 since it is an insufficient operating system to support

If I upgrade my OS will IRAF continue to run?

 Minor upgrades to the OS do not normally affect the operation of IRAF, but
major changes to the OS may.
	It should be stressed however, that after ANY operating system upgrade
which affects the system /dev or /usr directories, it is necessary to rerun
the IRAF install script to recreate image display fifo pipes in /dev and
symbolic links for /usr/include/iraf.h.  The install script in this case
must be run on all IRAF client machines in order to re-establish to
critical system links needed by all IRAF machines.

How difficult is it to port IRAF to my own system?

 The average individual will probably have great difficulty in porting IRAF
to their own system - IRAF is a big and complex system and one should not
underestimate the amount of work involved in a port.  We have had very few
successful ports done by people who were not highly skilled systems people
with some large degree of knowledge about IRAF internals.
	Unfortunately, the IRAF group does not have the resources to assist
with private ports, so anyone attempting this challenge is more or less on
their own.  For more information about IRAF ports see the README file in
iraf/v210/PORT in the IRAF network archive on the node

What window systems does IRAF run under?

 The only supported window system is X,  any X window manager should be
sufficient.  If you use X Windows then you will want to use XGterm for your
graphics terminal and XImtool as your image display server, these can be
downloaded as part of the X11IRAF package from /iraf/x11iraf in our archives.
Note that IRAF itself is not dependent on a window system, many non-graphics
tasks can be run from the raw console and older terminal such as VT640 may
also be used and would lack only an image display.

Is IRAF easy to install?

 The IRAF installation is straightforward but not trivial.  Source code,
object libraries, and executable are included in all distributions.
Installation guides and site managers guides are available for each
distribution in the same directory.  If the instructions are followed your
installation should go smoothly.  (One step of the installation does require
root privileges.)  

How widely used is IRAF?

 Since IRAF is available freely over the network we are only able to
estimate the number of sites or users.  Our records suggest there are
approximately 5000 users at about 1500 sites throughout the world.  Our
newsletter mailing list has roughly 1500 recipients.  These numbers indicate
that IRAF is a major software package in the US and abroad.

How do I acknowledge IRAF in a publication?

  There are two papers appropriate as references for IRAF in a
publication.  They are:
Tody, D. 1986, "The IRAF Data Reduction and Analysis System" in Proc. SPIE
        Instrumentation in Astronomy VI, ed. D.L. Crawford, 627, 733
Tody, D. 1993, "IRAF in the Nineties" in Astronomical Data Analysis Software
         and Systems II, A.S.P. Conference Ser., Vol 52, eds. R.J. Hanisch,
         R.J.V. Brissenden, & J. Barnes, 173.
The more recent paper includes more references.  Both are available from
the anonftp archive on in iraf/docs (see README).  No special
acknowledgement is required as a matter of policy so we don't blatantly
state these anywhere, but a mention is always appreciated.  A footnote
describing IRAF may also be used when appropriate:
    "IRAF is distributed by the National Optical Astronomy Observatories,
    which are operated by the Association of Universities for Research
    in Astronomy, Inc., under cooperative agreement with the National
    Science Foundation."