Here is a good question from Sanch:
I am trying to average spectral channels in an image cube. Can anyone suggest what's the best way
to do it in AIPS?
I don't want to go back to the UV data and re-reduce it to get the image, as the data I am
working on is huge (VLBI data).
And some more details:
She wants to average together channels in a channel map. In other words, she has a channel map with, say, 100 channels and she wants to turn it into a map with 50 channels. Channels 1 and 2 would be averaged together and become the new "Channel 1," channels 3 and 4 would be averaged together and become the new "Channel 2," and so on.
Thoughts, AIPS gurus?
If you have a question about AIPS that CANNOT be answered by reading the
2 comments:
when you use the task 'IMAGR'
it is possible to use
AIPS 1: NCHAV -1 Number of chan. to average.
AIPS 1: CHINC 1 Channel incr. between maps.
If you set both NCHAV and CHINC to be 2,
then you will average channels 1-2 3-4 5-6.. 99-100 etc. to be channel 1 2 3 ... 50.
I guess it's the best way.
I am sharing Eric Greisen's suggestion of binning spectral channels in an image cube.
He said " ..transpose the cube: task TRANS with TRANSCODE='312'
and then run SUBIM with XINC > 1. It gives you options of what is done with the pixels - select every XINC'th, average, take the MAX and take the MIN."
Thanks to everyone for brainstorming !
-Sanch
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