[daip] [!8690]: AIPS - Factor in CONVL

[Eric Greisen]

Eric Greisen updated #8690
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                 Due: - Cleared - (was: 20 July 2016 08:18 PM)

Factor in CONVL
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           Ticket ID: 8690
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/8690
           Full Name: Hansung Gim
               Email: hgim at astro.umass.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 18 July 2016 06:41 PM
             Updated: 18 July 2016 09:06 PM
      Resolution Due: 26 July 2016 08:18 PM (7d 23h 12m)



An unresolved source should have the same flux density
no matter what you do with convolutions.  Its brightness may
come out slightly different with convolution in Jy/beam.  Your
noise in Jy/pixel has dropped by about a factor of 5 but your
peak in Jy/pixel has dropped even more.  Convolution is good
for bringing up weak extended sources but it is equivalent to a 
serious taper in the initial imaging.  That taper down-weights
the longer spacings and so can raise the noise essentially by
including less of your data.

Eric Greisen




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