Introduction

FITSIO is a machine-independent library of Fortran-77 subroutines for reading and writing data files in the FITS (Flexible Image Transport System) data format. This library was written to provide a powerful yet simple interface for accessing FITS files which will run on most commonly used computers and workstations. This version of FITSIO supports all the features described in the official NOST definition of the FITS format and can read and write all the currently defined types of extensions, including ASCII tables (TABLE), Binary tables (BINTABLE) and IMAGE extensions. The FITSIO subroutines insulate the programmer from having to deal with the complicated formatting details in the FITS file, however, it is assumed that users have a general knowledge about the structure and usage of FITS files.

The FITSIO package was developed for use by the HEASARC (High Energy Astrophysics Science Archive Research Center) at the NASA Goddard Space Flight Center to convert various existing and newly acquired astronomical data sets into FITS format and to further analyze data already in FITS format. The latest version of the FITSIO source code, documentation, and example programs are all available on the World-Wide Web at the following URL:

       http://heasarc.gsfc.nasa.gov/fitsio

FITSIO also can be obtained from the HEASARC via anonymous ftp from heasarc.gsfc.nasa.gov in the software/fitsio/fortran subdirectory.

Any questions, bug reports, or suggested enhancements related to the FITSIO package should be sent to the author:

        Dr. William Pence                 Telephone:  (301) 286-4599
        HEASARC                           E-mail: pence@tetra.gsfc.nasa.gov
        Code 662
        NASA/Goddard Space Flight Center
        Greenbelt, MD 20771
        USA

This User's Guide assumes that readers already have a general understanding of the definition and structure of FITS format files. For further information about FITS formats, please obtain a copy of the `FITS User's Guide' and the `NOST FITS Standard', which are available from the NASA, Science Office of Standards and Technology at the address given below. Both of these documents are available electronically via anonymous ftp at nssdc.gsfc.nasa.gov in the /pub/fits directory. Any questions about FITS formats should be directed to the NOST, at:

        NASA, Science Office of Standards and Technology
        Code 633.2,
        Goddard Space Flight Center
        Greenbelt MD 20771
        USA
        WWW: http://ssdoo.gsfc.nasa.gov/astro/fits/fits_home.html
        E-mail: fits@nssdca.gsfc.nasa.gov
        (301) 286-2899

FITSIO users may also be interested in the FTOOLS package of programs that can be used to manipulate and analyze FITS format files. Information about FTOOLS can be obtained on the WWW at

        http://heasarc.gsfc.nasa.gov/ftools

or via anonymous FTP at

        heasarc.gsfc.nasa.gov /software/ftools/release