Add nrc_ta_image_comparison function to trending tools

[mperrin]

This adds a function nrc_ta_image_comparison which retrieves the TA image for a given visit, generates a matching simulation, and displays their difference. Useful as a check for binary.

For example, in particular 4502:126...

[codecov]

Codecov Report

Attention: 58 lines in your changes are missing coverage. Please review.

Comparison is base (55381cd) 54.78% compared to head (457bdf1) 54.34%.

Files	Patch %	Lines
webbpsf/trending.py	4.25%	45 Missing ⚠️
webbpsf/mast_wss.py	18.75%	13 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #789      +/-   ##
===========================================
- Coverage    54.78%   54.34%   -0.45%     
===========================================
  Files           16       16              
  Lines         6558     6621      +63     
===========================================
+ Hits          3593     3598       +5     
- Misses        2965     3023      +58     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[obi-wan76]

This is really good and it works as expected. I have a similar "residual" function that uses make_residual_image from PSFPhotometry in photutils.psf. I wonder if there is a way to quantify the residual image beside the visual inspection (stdev?)

[mperrin]

To quantify, a straightforward step would be to compute Chi^2, using the pipeline ERR extension estimate of the uncertainties.

[mperrin]

Yeah that was pretty easy to add. Now it looks like this. Note annotation text in rightmost panel:

[obi-wan76]

Looks really good, nice addition. Thanks!

[Skyhawk172]

I ran this function on all of WFS&C observations and found that, sometimes, the chi^2 does not catch all binaries, if that's its main purpose. I'm looking into other options.