AIPS NRAO AIPS HELP file for ONEBEAM in 31DEC19



As of Tue Dec 18 11:58:38 2018



HELP SECTION

ONEBEAM
Type: Adverb  (scalar)
Use:  To specify whether one beam is made for facet number 1 and
      applied to all facets or whether separate beams are computed for
      each facet.  Technically, each facet should have a separate beam
      since the u,v distribution is slightly different for each
      facet.  Since uv-plane Clean as done in IMAGR is an adaptive
      algorithm, the model containing any minor errors made in the
      minor Clean cycles due to the error in dirty beam will be
      correctly subtracted from the residual visibility data and the
      next cycle will attempt to undo those errors while refining the
      model.  Using ONEBEAM TRUE will speed up IMAGR by a bit and
      probably will not affect the answers much.  Very hgigh dynamic
      range imaging should be done with ONEBEAM FALSE.

Null value: <= 0 -> Compute beams for each facte
            > 0  -> compute one beam and apply it to all facets
Tasks:
    IMAGR........Fourier transforms and Cleans uv data with wide-field,
                 interactive TV, and data weighting options.
                 ONEBEAM affects how many beams are computed and used
                 and this will affect the speed and accuracy of the
                 results.

EXPLAIN SECTION


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