PRIMARY

          SHOW PRIMARY [PLANE|FIELD Kn] [First Last]

    Show some sub-cube of the (4-D) Primary Beams.

    The 2nd argument indicates whether SHOW shows all Fields for  a  given  fre-
    quency  plane  (PLANE keyword), or all Frequency-dependent beams for a given
    Field (FIELD keyword). The 2nd and 3rd arguments are optional if the beam is
    only 3-D, which occurs for a single field or a frequency-indepedent beam  in
    Mosaics (narrow band approximation).