[daip] Error in AIPS task FILLM in handling opacities

[gcastell at iafe.uba.ar]

Dear AIPS's people,

I am writing to you concerning a warning on the 31DEC08 version of FILLM
that I received via email several days ago.
Nowadays, I am reducing continuum data taken in direction to the supernova
remnant IC443.
The observations were carried out in a dual mode at 74 and 330 MHz. My
question is: Should I be careful with some problem in FILLM?
I think my situation is diferent from that you described in the email, but
I am not completely sure about it.

I will be very grateful if you could tell me something about problems in
the task FILLM  when observations are made in dual mode.

thank you very much in advance,
Best Regards,
Gabi


> To: All VLA users
> Subject: Error in AIPS task FILLM in handling opacities
>
> Dear colleague,
>
> The 31DEC08 (TST) version of FILLM had a problem with its handling of a
newly available band code in an observation.  In the period from
September
> 13 to October 20, 2008, FILLM was under the impression that the data it
was handling were in the band of the new scan rather than the band of the
> scan it still had to finish writing.  If your observations were all at
one band, then there is no problem.  If there were band changes during the
observation then the last record of each scan in CL table version 1 will
have opacities and antenna gains calculated for the (incorrect) band of
the next scan.  This can make a significant error if one of the bands is
at relatively high frequency.  This error can be repaired most simply by
deleting all CL tables including version 1 and running INDXR, or it can be
repaired by using a version of FILLM from a midnight job run after October
20, 2008.
>
> Please contact daip at nrao.edu if you have any further questions about the
quality of your data.
>
> Claire Chandler
> Deputy Assistant Director for Science, NM Operations
> _______________________________________________
> Vlavlbausers mailing list
> Vlavlbausers at listmgr.cv.nrao.edu
> http://listmgr.cv.nrao.edu/mailman/listinfo/vlavlbausers
>