[daip] [Vlavlbausers] Error in AIPS task FILLM in handling opacities

[Yoshiaki Hagiwara]

Dear Claire,

Regarding the problem with FILLM, I wonder if my data(AH979, Observ.
date=03-OCT-2008) are having opacity errors you mentioned below, since 
I observed changing frequencies during observations,

>This can make a significant error if one of the
> bands is at relatively high frequency.

In my observations, the difference of frequency change is less than 100
Mhz
within K-band. Do you think it caused significant errors?
I don't think that my data are affected by the problem
below.

Thanks.

Best,
Hagi


2008-11-05 (水) の 14:15 -0700 に Data Analysts さんは書きました:
> 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
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