[daip] [!5480]: aips - CVEL AIPS 2

[Eric Greisen]

Eric Greisen updated #5480
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              Status: Closed (was: Open)
                 Due: - Cleared - (was: 24 October 2014 05:35 PM)

CVEL AIPS 2
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           Ticket ID: 5480
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/5480
           Full Name: Carolina Rodriguez
               Email: ca.rodriguez at crya.unam.mx
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Closed
            Priority: Default
      Template Group: Default
             Created: 11 September 2014 10:45 PM
             Updated: 22 October 2014 06:55 PM



You seem to have described a system that worked just like
one would want it to work.  The velocity when you are done
is -17.6 at channel 64 because you told CVEL to adjust the
data to make that be true.  It does this in great detail, with the
shift being a little different in each scan (and very slightly with
the VLA even with each antenna) and being quite different in
runs 5 days apart.  In the end all data had the visibilities shifted
in channels so that channel 64 is -17.6 at the center of the field
for all samples.  The Doppler effect and the rotation and motion
of the Earth are why CVEL does slightly different things with
each scan and what it does is correct for that so that the
data will give at the requested channel the requested LSR velocity.
I think you have run CVEL correctly and gotten correct results -
there is no need to change anything.

Do you have any evidence that it did wrong things?  If the
imaging gives curious and poor behavior or something of that
sort then we should look more deeply.

Note that you could combine the 2 observing runs in one
data set with DBCON to do better imaging with all of your
integration and UV sampling.

Stop worrying over this and go on - all seems well at least from what
you have so far told me.

Eric Greisen




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