[daip] [!4188]: aips - blanking in GBT maps

[Eric Greisen]

Eric Greisen updated #4188
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       Staff (Owner): Eric Greisen (was: -- Unassigned --)
                 Due: - Cleared - (was: 25 December 2013 12:00 AM)

blanking in GBT maps
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           Ticket ID: 4188
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/4188
           Full Name: Trisha L Ashley
               Email: trisha.ashley at gmail.com
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: ALMA E2E
      Template Group: Default
             Created: 22 December 2013 08:47 PM
             Updated: 23 December 2013 06:27 PM
      Resolution Due: 01 January 2014 12:00 AM (8d 5h 32m)



There may be several issues here.  The blanked pixels are
created by SDGRD since you have not observed at every
position (usually) in the output image - otherwise you would be
dropping some data off the edges most likely.

But I see another issue - the projection -GLS is not simple.
Reference declinations that are not zero cause the whole thing
to be gridded on an oblique projection that may be nothing like
you expected or wanted.   Frankly, I do not know what SDGRD
will now do with these projections and it would be good for me
to get my hands on a sample data set to try things out.  Perhaps
you could put a FITS file of the UV data somewhere I could find it.

I your case, however, look at some of your channel images with
CBTR on the TV with DOCIRCLE true to see if the coordinates
are anything like what you expect.  Perhaps try SDGRD with
the -SIN projection which does not go into this oblique business.

In XMOM you want ICUT=0, FLUX=-1000000.

Eric Greisen




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