DEFINE FITS

        [SIC\]DEFINE  FITS  Var  File  [index|T|B]  [T|index|B]  [index|T|B]
    [/GLOBAL]

    Define  variables  associated  to  the keywords and data of a FITS file.
    The defined variables depend on the FITS file content. Both "basic" FITS
    files and FITS extension (XTENSION) are handled.

    An 'index' value may be added to read only the 'index'-th extension.

    With  'B'  code  (stands for Basic): define only the basic keywords, not
    proprietary keywords. In particular suppress HIERARCH keyword  structure
    present in ESO FITS headers.

    The  'T' code may be added to get all multidimensional arrays transposed
    (depending on how the FITS file was written, sometimes the dimensionali-
    ty  of  the  SIC variables created from the FITS structure is not handy.
    Using the transposition code can be a solution then).

    For basic FITS data, the following variables are defined

       VAR%NDIM       Integer        Number of dimensions
       VAR%DIM        Integer[4]     Dimensions
       VAR%CONVERT    Double[3,4]    Conversion formulae for the 4 axes:
                                     Reference pixel,
                                     Value at reference pixel,
                                     Increment
       VAR%DATA       Real           FITS data array
    The variables are defined as part of a structure.  GreG  command  LIMITS
    /RGDATA A recognizes such a basic FITS structure in much the same way as
    GILDAS images.

    The DEFINE FITS command tries to define a SIC structure  which  contains
    all  FITS  keywords,  as  well as all binary and ASCII tables located in
    FITS extensions.

    Support for Random groups (although this is an obsolescent  FITS  struc-
    ture, it is still widely used) is also available.

    DEFINE FITS only works to read FITS files, but not to create them.