UV_FIELDS

        [CLEAN\]UV_FIELDS RaVar DecVar [Unit] [/CENTER Ra Dec] /FILE File

        ***** Experts Only **** Not intended for general use ******

        Replace fields ID by Fields offsets in a Mosaic UV Table.  This can only
    work for a Mosaic UV table with Fields offsets, or Phase center offsets.  It
    cannot operate on a UV table with Pointing center offsets.

    For  files imported from UVFITS, the Fields offsets are found in the AIPS SU
    Table which is not decoded by the FITS command, but only through the  DEFINE
    FITS command.

    The UV_FIELDS command allows to convert the Field IDs column of the UV table
    into  Phase Offsets columns, and insert the proper coordinates.  Unit speci-
    fies the unit of the RaVar and DecVar variables. It can be  DEGREE,  MINUTE,
    SECONDS, RADIAN or ABSOLUTE.

    If  ABSOLUTE, RaVar and DecVar are assumed to character variable arrays han-
    dling the Right Ascension and Declinations of the fields expressed in  sexa-
    gesimal format.

    The  typical  use  is after a DEFINE FITS A File.uvfits command, which gives
    the   (Ra,Dec)   positions   of   the   field   centers   in   Degrees    in
    A%aips_su%col%raepo and A%aips_su%col%decepo variables:

        fits File.uvfits to File.uvt
        define fits A File.uvfits HEADER
        compute ra mean a%aips_su%col%raepo
        compute dec mean a%aips_su%col%decepo
        define double ra dec
        define char*16 cra cdec
        let cra ra /sexag d H
        let cdec dec /sexag d d
        !
        uv_fields a%aips_su%col%raepo a%aips_su%col%decepo DEGREE -
          /FILE File.uvt /CENTER 'CRa' 'CDec'
        !
    This  command  is used in the fits_to_uvt.ima script. Note that a proper use
    also requires to set the reference coordinate to Ra and Dec consistently  in
    the UV Table.