PRIMARY

        PRIMARY

    Apply  primary beam correction to an interferometer map (i.e. DIVIDE the
    input image by the primary beam). The primary beam is assumed  to  be  a
    Gaussian.  After  this correction, the noise is increasing exponentially
    with the distance to the map center, and the resulting image has thus to
    be truncated at some radius.

    For  the  Plateau de Bure interferometer, the typical values of the FWHM
    primary beam is:
              58" at 85 GHz (3.5 mm)
              50" at 100 GHz (3 mm)
              43" at 115 GHz (2.7 mm)
              21" at 230 GHz (1.3 mm)