[daip] [!4042]: aips - PBCOR

[Eric Greisen]

Eric Greisen updated #4042
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                 Due: - Cleared - (was: 15 November 2013 12:00 AM)

PBCOR
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           Ticket ID: 4042
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/4042
           Full Name: Lynn D Matthews
               Email: lmatthew at haystack.mit.edu
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): Amy Mioduszewski
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: ALMA E2E
      Template Group: Default
             Created: 07 November 2013 04:08 PM
             Updated: 13 November 2013 08:33 PM
      Resolution Due: 18 November 2013 11:08 PM (5d 2h 34m)



PBCOR uses - correctly - the pointing position "obs" position as the center
of the beam.  IMHEADER does not show this value when it is pure 0 or when
it matches the phase stopping position shown in the RA-- and DEC- lines.
The source table format was revised to include the pointing position -
columns which should have been there all along - and the tasks use the
values in those columns now.  A default in the absence of information is
to assume the pointing and phase stopping positions are the same.

The issue with your PBCOR is to figure out why the pointing position in the
image header and the phase stopping position are not the same.  You 
should look back at the UV multi-source data sets that led to the present
image to find out why.  Note that PBCOR does have the COORDINA adverb
so, if it is not zero, the COORDINA value rather than the "obs" value is used.

Eric Greisen




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