Include IRAFStarFinder option for tweakreg_catalog

[thomaswilliamsastro]

This PR allows users to swap between the default DAOStarFinder and IRAFStarFinder for source catalog in the tweakreg step. In some cases (particularly for shorter bands where the PSF is more undersampled), I've found this produces better results, and this is also seen in some of the discussion in #6295. It now gets exposed as a switch 'dao'/'iraf', but the other parameters are passed to it exactly the same way as DAOStarFinder

Checklist for maintainers

• [x] added entry in CHANGES.rst within the relevant release section
• [ ] updated or added relevant tests
• [x] updated relevant documentation
• [x] added relevant milestone
• [x] added relevant label(s)
• [ ] ran regression tests, post a link to the Jenkins job below. How to run regression tests on a PR
• [ ] Make sure the JIRA ticket is resolved properly

[codecov[bot]]

Codecov Report

Patch coverage: 25.00% and project coverage change: -0.02 :warning:

Comparison is base (930628f) 77.60% compared to head (81c18f5) 77.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7024      +/-   ##
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- Coverage   77.60%   77.59%   -0.02%     
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  Files         452      452              
  Lines       36193    36197       +4     
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- Hits        28088    28086       -2     
- Misses       8105     8111       +6     

Flag	Coverage Δ		*Carryforward flag
nightly	77.61% <ø> (-0.01%)	:arrow_down:	Carriedforward from 930628f
unit	49.72% <25.00%> (-0.01%)	:arrow_down:

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Impacted Files	Coverage Δ
jwst/tweakreg/tweakreg_step.py	61.31% <ø> (ø)
jwst/tweakreg/tweakreg_catalog.py	69.56% <25.00%> (-25.18%)	:arrow_down:

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[mcara]

I think it would be useful to get @larrybradley opinion.

[mcara]

My main concern is a constantly growing number of parameters in this automated pipeline step. IMO, users would benefit greatly from using stand-alone data analysis packages photutils (or SExtractor or whatever they choose) and tweakwcs.

For example, previously it was requested to support user-provided catalogs. There is a PR for that: https://github.com/spacetelescope/jwst/pull/7022 In this context, my philosophical question is whether it makes sense to increase the number of options for this step or should the users use photutils to create custom catalogs and pass them to the tweakreg step...

This PR looks fine from the technical point of view so I am going to approve it but I will leave the decision to merge it to @hbushouse

[mcara]

There are many ways users may want to make specialized catalogs (star finders, segmentation based, PSF fitting, etc.)

Just to add to the list, see https://github.com/spacetelescope/jwst/issues/6962

[thomaswilliamsastro]

I agree with these comments, but while a catalogue can be passed to tweakreg for the final step aligning everything to an 'absolute' frame, there isn't such functionality to pass either a catalogue function or individual catalogues for each tile for the relative alignment at the moment

[mcara]

... while a catalogue can be passed to tweakreg for the final step aligning everything to an 'absolute' frame, there isn't such functionality to pass either a catalogue function or individual catalogues for each tile for the relative alignment at the moment

That is exactly what https://github.com/spacetelescope/jwst/pull/7022 will do (shortly). In my personal experience, IRAFStarFind is not as important or accurate as DAOStarFind and it might require different values for other parameters. And as @larrybradley mentioned above, there are many other ways of finding sources, including external packages such as SExtractor.

Given that https://github.com/spacetelescope/jwst/issues/7022 is about to be merged soon, I do not see the need for this additional complication.

[nden]

@thomaswilliamsastro Sorry for the late response. We discussed the proposed change internally and decided not to accept it. The pipeline now supports custom user-provided catalogs not only for the absolute astrometric alignment but also for the relative alignment - see #7022 . In addition, we don't want to increase the complexity of the interface and think adding another parameter is undesirable.