[daip] [!5478]: aips - corrected ticket about CVEL AIPS

[Carolina Rodriguez]

Carolina Rodriguez updated #5478
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corrected ticket about CVEL AIPS
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           Ticket ID: 5478
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/5478
           Full Name: Carolina Rodriguez
               Email: ca.rodriguez at crya.unam.mx
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 11 September 2014 06:47 PM
             Updated: 11 September 2014 06:47 PM
                 Due: 15 September 2014 06:47 PM (4d 0h 0m)
      Resolution Due: 19 September 2014 06:47 PM (8d 0h 0m)



Hello,

I'm working with maser line data taken in 2008 with the VLA-EVLA transition. The observations were dinamically scheduled so now I'm trying to apply doppler corrections with the CVEL task but I don't understand what is happening, exactly. I have specified in the aparm option of CVEL the reference channel, the rest frequency, the velocity of the source (the velocity that corresponds to the day that the observations were planned but the observations were made 3 days later than planned) and the velocity type. After that, I was expecting that the velocity information will change in the header but was not the case. The velocity in the header is still the same before and after the application of CVEL to the data.

I inspected the data with the POSSM task and I see that the original UV data in my SPLIT were shifted in comparation with the CVEL data but I don't know what CVEL has done, exactly. 
I hope I explained my problem well, I'm a begginer with AIPS! 

Please, can you give me some information of how CVEL works? the information in the HELP/EXPLAIN part of AIPS is not enough for my complete understanding. Another question that I have is about the sky frequency, where is CVEL computing that? and how relates all the parameters (as rest frequency, velocity, position of the source, etc) with the sky frequency?

I'll be waiting for your help!
Thank you very much,

Carolina

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