IRAF – Image Reduction and Analysis Facility

IRAF is the Image Reduction and Analysis Facility, a general purpose software system for the reduction and analysis of astronomical data. This is primarily data taken from imaging array detectors such as CCDs.

The main IRAF distribution includes a good selection of programs for general image processing and graphics, plus a large number of programs for the reduction and analysis of optical and IR astronomy data (the “noao” packages). Other external or layered packages are available for applications such as data acquisition or handling data from other observatories and wavelength regimes such as the Hubble Space Telescope (optical), EUVE (extreme ultra-violet), or ROSAT and AXAF or Chandra (X-ray).

It has been in use since its inception in 1981 by National Optical Astronomy Observatory (NOAO). Development and maintenance of IRAF is discontinued since 2013.

Features include:

  • Highly modular.
  • General image processing:
    • Tools for reading and writing data in the transportable FITS format.
    • Interactive graphics and image display tools for examining your data.
    • Tools for image registration and cleaning bad pixels.
    • Variety of smoothing operators.
    • Tools for image arithmetic, image statistics and combining image frames.
  • Spectral data:
    • Rich selection of tools for spectral reduction and analysis in the NOAO package that spans 1-d, 2-d, echelle, and fibor spectroscop.
    • 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.
    • Multitude of tasks for manipulating spectra in general.
  • Direct imaging data:
    • Tools for basic CCD reductions.
    • Mosaicing.
    • Aperture and PSF-fitting (DAOPHOT) photometry.
    • Photometric calibration.
  • Process astronomical data.
  • User-defined tasks:
    • Procedure scripts.
    • Subset pre-processor programs.
  • Command line interface.
  • Offers software developers a rich programming environment that includes file management tools, interactive graphics and display, portability, and more.
  • Process data that is similar to astronomical data.

Support: Documentation
Developer: National Optical Astronomy Observatory
License: Generally MIT license

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