[daip] Error in AIPS task FILLM in handling opacities

[Amy Mioduszewski]

Dear Gabi,

Since you are doing low frequency it should not effect you, I guess "relatively 
high frequency" should have been defined more quantitatively.

Amy

gcastell at iafe.uba.ar wrote:
> 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
>>
> 
> 
> 
> 
> 
> 
> 
>