[daip] [!15373]: AIPS - AIPS APCAL opacity correction

[JongHo Park]

JongHo Park updated #15373
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AIPS APCAL opacity correction
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           Ticket ID: 15373
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/15373
                Name: JongHo Park
       Email address: jhpark at astro.snu.ac.kr
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 29 December 2019 09:34 AM
             Updated: 07 January 2020 07:05 AM
      Resolution due: 30 September 2022 12:00 AM (996d 16h 54m)

Dear Dr. Greisen,


Thank you very much for your kind response.

Please find the attached PRTAB file of the TY table.

Even if I am currently looking at 86 GHz data, I sometimes saw some offsets between different IFs in Tsys vs secz plots for other lower frequency data (though not as severe as the current one). If you look at the attached AIPS_APCAL.png, we cannot see the offsets between different IFs for LCP. The fitting result is somewhat strange with the obtained opacity being all negatives. I also tried to run APCAL for each IF. Please have a look at the attached APCAL_IF2.png and APCAL_IF7.png. It seems that the fitting works well for some IFs showing relatively low Tsys values, while it doesn't for the IFs showing high Tsys values.

Given the situation, I'm trying to fit the receiver temperature value for each IF by myself and run APCAL with the TRECVR parameters given for each IF with DOFIT = 0. I am wondering whether this idea makes sense or not and would be glad to listen to your opinion.


Best Regards,

Jongho Park

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