Support for subarrays¶
Support for subarrays is currently only implemented for the imager and it supports datasets where only a custom subset of the 2D array is observed.
The keywords of IRISImageModel which defines the parameters of the
subarray are:
model.meta.subarray.name = "CUSTOM"
model.meta.subarray.id = 1
model.meta.subarray.xstart = xstart + 1
model.meta.subarray.ystart = ystart + 1
model.meta.subarray.xsize = xsize
model.meta.subarray.ysize = ysize
Consider that following the FITS conventions the xstart and ystart keywords
are 1-based, therefore the default xstart is 1 and if you are slicing an
array in Python, you should add 1 to the keyword before saving it into the metadata.
subarray.id is saved into the FITS keyword SUBARRID and should be 0 for full
frames, 1 for the first subarray and so on.
The name of an entire frame is “FULL”.
Subarrays and reference files¶
Flat frames, darks and background files either in CRDS or using local overrides can either be saved as subarrays or can be saved as full frames. In case they are saved as full frames, after being accessed they are sliced according to the metadata in the input subarray.
Example usage¶
As usage examples, check the notebooks or the test_image2.py script in the
unit tests folder in the repository