Expand on trace

[melanieclarke]

Proposal to expand trace-based extraction to all use_source_posn cases.

A couple things to note:

• I added a MIRI trace calculation, similar to the NIRSpec one you implemented.
• I added bounding box handling to both trace calculations. This doesn't affect NIRSpec much, but it affects MIRI LRS a lot.
• I kept the trace_offset parameter, but expanded its usage. It can now be used to tweak any aperture definition.
• I removed the use_trace parameter, since it's redundant with use_source_posn. A trace is now computed anytime a source position is.
• BOTS now defaults to use_source_posn=True.
• Docs will need updating if we like these changes.

Let me know what you think - I'm eager to get something like this in because it folds in nicely with the work we're doing for optimal extraction. In particular, with these changes, I can get the optimal extraction we developed for MIRI LRS working with a toy NIRSpec PSF model very straightforwardly.

[hayescr]

Thanks for making these changes @melanieclarke! I just had two small questions, otherwise I'm happy to merge this in as is.

[melanieclarke]

A question for you -- do you think we should rename trace_offset to position_offset? I'm wondering if "trace" is confusing, since it's also applied to background regions.

[hayescr]

I'd be up for changing it, especially now that it's more generally applicable. position_offset sounds fine, the only other idea I had was something like aperture_offset since it will offset all apertures?

[melanieclarke]

Okay, thanks, I can update that too. Unless you object, I think I like position_offset better, by analogy to the existing use_source_posn parameter. I'm not sure the background regions are consistently understood as "apertures".

[hayescr]

Nope, no strong preference, position_offset is fine with me.

[melanieclarke]

Okay, done!

[hayescr]

Thanks again I'll merge this in and update add some documentation updates!