[daip] [!12019]: AIPS - AIPS clcorprm(8,9) reference time

[Jackie Villadsen]

AIPS clcorprm(8,9) reference time
---------------------------------

           Ticket ID: 12019
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/12019
                Name: Jackie Villadsen
       Email address: jrv at astro.caltech.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 09 May 2018 12:25 AM
             Updated: 10 May 2018 12:42 AM
           Reply due: 14 May 2018 12:42 AM (4d 0h 0m)
      Resolution due: 02 February 2021 12:00 AM (998d 23h 18m)

Thanks Eric!  Yes, the UVCETI field used a constant pointing coordinate
throughout the whole observation, but I need to remove about a
milli-arcsecond's worth of proper motion over the course of 4 hours.  I
think I should be good now that I know that all the coordinates have been
shifted to IAT 0 on the reference date - that will enable me to compare the
position between epochs accurately given the known proper motion.

Thanks!

Jackie

On Wed, May 9, 2018 at 3:33 PM, Eric Greisen  wrote:

> A good question and I am not sure I am happy with the answer.
>
> It uses IAT 0 on the reference date.  In other words it
>
>       RAINT = CLCORP(8) * Time
>
> where time 0 is midnight IAT on the header reference date.
> Assuming the observation was made at a position relevant
> to the start of the first scan on uvceti then it over-corrects
> by the time of that first scan.  I suspect that (when INFILE
> is not used) there should be a t0 specified in some way,
> e.g. CLCORP(10) or something.
>
> I am assuming that uvceti had a constant coordinate
> through the data set and now needs phase shifting so
> that all times line up.  I expect that the zero time is not
> all that important but you will need to take the imaged
> coordinate and correct for the t0.
>
> Eric Greisen
>
>
>
> Ticket Details
> ------------------------------
> Ticket ID: 12019
> Department: AIPS Data Reduction
> Type: Issue
> Status: Open
> Priority: Default
>
> Helpdesk: https://help.nrao.edu/index.php?
>



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