FITS

        LAS\FITS READ  File[.fits]
        LAS\FITS WRITE File[.fits]  /MODE   SPECTRUM|INDEX   [/BITS   Nbits]
    [/CHECK]

    Either  READ  the File.fits FITS file to the CLASS internal data format.
    Please note that not all FITS files may be read by CLASS, and some head-
    er  information  might  be incomplete when doing so. Alternatively, FITS
    cubes can be converted to the Gildas Data Format  by  the  command  VEC-
    TOR\FITS, and then imported as a Class index by the command ANALYSE\LMV.

    Or WRITE the File.fits FITS file from the CLASS  internal  data  format.
    /MODE is a mandatory option which can take the following values as argu-
    ment:
      SPECTRUM a simple FITS file is written from the  current  spectrum  in
               memory  is  written.  The  number of bits per intensity value
               used when writing the FITS file may be controlled through the
               /BITS  optional argument. It can be: 16 or I*2 (2 bytes inte-
               ger), 32 or I*4 (4 bytes integer) or -32 or R*4 (4 bytes  re-
               al). Default is 32.
      INDEX    a  FITS  BINTABLE  is written from all the spectra in current
               index. The USER MUST make sure that  all  index  spectra  are
               consistent  (same  source,  same  line, same frequency setup,
               ...). The intensity values (and irregularly  sampled  X  axis
               values, if any) are always written as 4 bytes real.
    The  default  mode  and number of bits can also be specified through the
    commands:
      SET FITS MODE SPECTRUM|INDEX
      SET FITS BITS Nbits
    The option /CHECK will print the FITS HEADER on the terminal.