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UV_FIELDS

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

        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 specifies the unit of the RaVar and DecVar variables. It can be DE-
    GREE, MINUTE, SECONDS, RADIAN or ABSOLUTE.

    If  ABSOLUTE,  RaVar and DecVar are assumed to character variable arrays
    handling the Right Ascension and Declinations of the fields expressed in
    sexagesimal 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
        define double ra dec
        define char*16 cra cdec
        let cra ra /sexag d H
        let cdec dec /sexag d d
        compute ra mean a%aips_su%col%raepo
        compute dec mean a%aips_su%col%decepo
        !
        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  consis-
    tently in the UV Table.


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Gildas manager 2023-06-01