[daip] [!8172]: AIPS - Incorrect flux scale after using CONVL with opcode IMAG

[Eric Greisen]

Eric Greisen updated #8172
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                 Due: - Cleared - (was: 18 March 2016 11:40 PM)

Incorrect flux scale after using CONVL with opcode IMAG
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           Ticket ID: 8172
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/8172
           Full Name: Blazej Nikiel-Wroczynski
               Email: iwan at oa.uj.edu.pl
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 16 March 2016 11:40 PM
             Updated: 17 March 2016 09:32 PM
      Resolution Due: 24 March 2016 11:40 PM (7d 2h 8m)



I do not have a satisfactory answer for you.  The task
literally does what is says it will do and in the case of a Gaussian
things are really well controlled and the units can come out as
they should.  However, when you FFT a dirty beam you get an
image of the weights used in making it and they are not well
controlled.  The imaging tasks simply make the beam and the image, 
find the peak of the beam (often 10^6 or something) and normalize
it to 1.0 (hence Jy/beam) and use the same scale for the image.

I am not surprised that the scale did not come out as one would
wish.  The image should be correct within a factor (and including the
various comments about inner quarter and the like).

Eric Greisen




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