[daip] AIPS memory allocation / Re-defining phase-center {External}

[Felix Pötzl]

Hello,

I have had some trouble with AIPS dealing with datasets with small time 
and frequency spacing. I am working on some archival data set now with 
0.1 s integration time and 62.5 kHz channel spacing, where sources are 
sometimes expected to be found several arcseconds from the correlation 
phase center.

To find the source far off-centre, I set large windows in delay and rate 
space while running FRING. The output that AIPS gave initially for too 
large windows and/or short solution intervals looks like this: "FRNSRC: 
DID NOT GET WHAT I NEED FOR MEMORY" and then proceeds to ask for shorter 
solution intervals and/or smaller windows for delay and rate. I have set 
the maximum allocatable memory with SETMAXAP, which now allows for 
larger windows to be tested.

However, I am still wondering if there is a more elegant solution to 
alleviate the memory issue and dealing with very large delay and rate 
windows. Is it possible in AIPS, post-correlation, to re-define the 
phase centre that is used in the fringe search? In this way, one could 
use potential prior information about the source position to use smaller 
windows, and thus make the fringe-fitting process faster and increase 
the SNR of solutions.

I would be very thankful for any feedback on this. Maybe I am missing 
something obvious.

Best regards,
Felix Poetzl

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Felix Pötzl
Postdoctoral Researcher
FORTH Institute for Astrophysics, Heraklion, Crete
Office: 233 Physics Bldg.
Phone: (+30) 2810-394233
https://www.ia.forth.gr/people/Poetzl
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