UV_CHECK BEAM_RANGES
Keywords: imager

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UV_CHECK BEAM_RANGES

          UV_CHECK BEAMS returns a variable named BEAM_RANGES[3,Nbeam] where
          Nbeam is the number of different synthesized beams found in the UV
          data (based on the visibility weights).

          BEAM_RANGES[1,i]  is the first channel of Beam number i
          BEAM_RANGES[1,2]  is the last channel of Beam number i
          BEAM_RANGES[1,3]  is the total weight of visibilities of Beam number i

          BEAM_RANGES is later used by UV_PREVIEW to discard edge channels
          that often do not have the same weights as the bulk of channels.

          Variable NBEAM_RANGES indicates the number of beam ranges. It is -1
          if UV_CHECK has not yet been used.

          Most automatic imaging processes will assume BEAM_RANGES is relatively
          simple (2 edges and a dominant main  range)  and  simply  discard  the
        edges
          if any, or complain if is too complex.

          For complex datasets with NBEAM_RANGES greater than 2 or 3,
          BEAM_RANGES could be used to segment the imaging and deconvolution
          process into ranges having a common beam. Setting MAP_BEAM_STEP
          to 1 is another possibility, but that creates 1 beam per channel,
          thus doubling the used space.