[daip] [!9188]: AIPS - PBCOR error in AIPS?

[Scott Hyman]

Scott Hyman updated #9188
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PBCOR error in AIPS?
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           Ticket ID: 9188
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/9188
           Full Name: Scott Hyman
               Email: shyman at sbc.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 21 October 2016 09:17 PM
             Updated: 21 October 2016 09:17 PM
                 Due: 25 October 2016 09:17 PM (4d 0h 0m)
      Resolution Due: 31 October 2016 09:17 PM (10d 0h 0m)



Hi Eric,

I read Rick's memo on the new primary beam characteristics (EVLA MEMO 195) which includes new parameters for P-band observations.  The VLA Obs. Status Summary for 2017A indicates these have been updated in AIPS.  I am running 31DEC16 version on a MacPro.  When I apply PBCOR with the default parameters on a 296 MHz (16 MHz bandwidth) image made from a March 2014 A configuration observation about 2 deg from the Galactic Center, the correction factor for the peak pixel is 1.7.  When I input Rick's new parameters into the PBPARMS, I get 4.4x.  When I calculate the correction manually, I also get 4.4, which does seem to be more realistic for 2 deg away.   

I think I found the error.  Using the default PBPARMS, the history file below shows the 296 MHz parameters as -1.125E-03, 5.27E-07, and 9.6E-11, but Rick's memo says they should be:

-1.125E-03, 5.27E-07, -1.14E-11, and 0.96E-14

Scott

 1463  PBCOR RELEASE ='31DEC16 '  /********* Start 21-OCT-2016   16:57:07
  1464  PBCOR INNAME='SNRIF1      '   INCLASS='ICL001'
  1465  PBCOR INSEQ=    0   INDISK=  1
  1466  PBCOR OUTNAME='BLAH        '   OUTCLASS='PBCOR '
  1467  PBCOR OUTSEQ=    0   OUTDISK=  1
  1468  PBCOR BLC=   1,   1,   1,  1,  1, 1, 1 TRC= 512, 512,   1,  1,  1, 1, 1
  1469  PBCOR PRA=  17 45 40.050  PDec= -29 00 27.90
  1470  PBCOR Beamcut=  0.10000   /Clip outside this beam value
  1471  PBCOR DOINVERS =-1.0   / > 0 multiply by beam
  1472  PBCOR / Beam =  1.000000E+00 +     / Beam  model
  1473  PBCOR /        -1.106000E-03 * X +
  1474  PBCOR /         5.110000E-07 * X*X +
  1475  PBCOR /         9.100000E-11 * X*X*X +
  1476  PBCOR / Where X = [Angle(arcmin) * f(GHz)]**2
  1477  PBCOR / above from EVLA 2016 model interpolated between   0.281 GHz
  1478  PBCOR / and   0.296 GHz parameters below
  1479  PBCOR / Beam =  1.000000E+00 +     / Beam  model
  1480  PBCOR /        -1.125000E-03 * X +
  1481  PBCOR /         5.270000E-07 * X*X +
  1482  PBCOR /         9.600000E-11 * X*X*X +
  1483  PBCOR / Where X = [Angle(arcmin) * f(GHz)]**2 


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