[daip] FRING fails after calibration with ACSCL

[Walter Brisken]

Hi Amy and DAIP,

I guess Eric may be back now.  Please let me know if any additional input 
is needed here.  I think this is an issue worth investigating sooner 
rather than later as it could well lead to confusing failures for folks.

I'll be in Socorro next week if need to chat.

 	Cheers,

 	Walter

On Mon, 8 Oct 2018, Amy Mioduszewski wrote:

> Hi Walter,
>
> Eric is away unfortunately and I don't really feel comfortable digging into 
> FITLD.  Eric is back Oct 16.
>
> Amy
>
> On 10/07/2018 04:30 AM, Walter Brisken wrote:
>>
>>  Hi DAIP,
>>
>>  I'm working on VLBA dataset BB397A on parallax, user=397 indisk=1 catnum=1
>>  .  FRING reports SNR=0 after application of calibration from task ACSCL
>>  even though the delays are reported correctly in the verbose messaging.
>>  Prior to application of ACSCL calibration (which generated SN3 and merged
>>  into CL5), FRING SNRs were very high (100s).
>>
>>  My suspicion is that recent changes to FITLD to change the visibility
>>  weights are triggering the problem.  This claim is supported by a test I
>>  ran where I used version='NEW' for FITLD, then switched back to
>>  version='TST' for the remainder of the calibration.  In this case, SNR
>>  values are back to expected levels.  This was done as user=397
>>
>>  The details of the data reduction are found in AIPS script:
>>  /home/parallax/VLBA/BB388/scripts/BB397A.cal
>>
>>  If you want to run the data reduction script, note that BB388LINKS points
>>  to /home/parallax/VLBA/BB388/links
>>
>>      -Walter
>> 
>

-- 
-------------------------
Walter Brisken
Director
Long Baseline Observatory
(575)-835-7133 (office)
(505)-234-5912 (cell)