[daip] [!6488]: aips - Flagging issues

[Robert H Gray]

Robert H Gray updated #6488
---------------------------

Flagging issues
---------------

           Ticket ID: 6488
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/6488
           Full Name: Robert H Gray
               Email: roberthansengray at gmail.com
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 20 April 2015 09:42 PM
             Updated: 20 April 2015 09:42 PM
                 Due: 22 April 2015 09:42 PM (2d 0h 0m)
      Resolution Due: 28 April 2015 09:42 PM (8d 0h 0m)



Hi!

I have an oddity affecting quite a bit of my data, and wonder if you can suggest how to do to figure out what’s wrong (using AIPS, which is why I’m sending this to the AIPS desk; kindly point me elsewhere if more appropriate).

UVPLT of Flux vs Distance for 3C48 shows an expected band across all baselines at 16 Jy for this initially calibrated data, but also a heavy band at 22 Jy, and a sprinkle at 33 Jy – after flagging one antenna that UVFND showed was involved in a sprinkle at 50 Jy—and these bands extend across all baselines.  

I’ve looked at the data with UVPLT in several ways trying to find the problem:  Flux vs Time (a few hot times, but the bands go across most times), and Flux vs Channel (no obvious hot channels).  I tried flagging everything over 20 Jy with UVGFLG and it seems that most records were partly flagged, and now POSSM never completes—I suspect because it takes forever to apply so many flags.  Is that likely to be right?  If so, I can see I need a better strategy...

Any thoughts?  Any task better suited?  I’ll attach a plot.

Thanks for any suggestions!

Bob Gray


------------------------------------------------------
Staff CP:  https://help.nrao.edu/staff