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oirlab / liger_iris_pipeline

Data Reduction System (DRS) for the Thirty Meter Telescope IRIS imager/spectrograph
https://oirlab.github.io/iris-pipeline
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Default subarray keywords for full frames #13

Closed zonca closed 4 years ago

zonca commented 4 years ago

@nils-erik @arunsurya77

I see that the default subarray parameters coming from the simulator are:

SUBSTRT1=1, SUBSTRT2=1, SUBSIZE1=4096, SUBSIZE2=4096

for a full array, shouldn't we have the SUBSTRT keywords be 0? or do you have any convention I don't know about arrays starting at 0 or 1?

arunsurya77 commented 4 years ago

I am not sure why these keywords are not XSTART,YSTART,XSIZE,YSIZE. maybe it's an old file. Also yes you are correct, the start should be 0. XSTART=0,YSTART=0

On Mon, 20 Jan 2020 at 10:36, Andrea Zonca notifications@github.com wrote:

@nils-erik https://github.com/nils-erik @arunsurya77 https://github.com/arunsurya77

I see that the default subarray parameters coming from the simulator are:

SUBSTRT1=1, SUBSTRT2=1, SUBSIZE1=4096, SUBSIZE2=4096

for a full array, shouldn't we have the SUBSTRT keywords be 0? or do you have any convention I don't know about arrays starting at 0 or 1?

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zonca commented 4 years ago

@nils-erik could it be due to IDL being 1-based instead of 0-based? I'll change all the files to have xstart and ystart at 0, but we should make sure to propagate it back to the simulator.

zonca commented 4 years ago

actually I take it back, checking JWST code [1], the default xstart and ystart is supposed to be 1, I think that is due to the fact that the FITS file format defaults to 1-based indexing. So let's use the same default in IRIS.

[1] https://github.com/spacetelescope/jwst/blob/187a6cf97ffef368699b6fff5d4925ecacd4a0f1/jwst/lib/reffile_utils.py#L100