Flux calibration

[JuergenSchreiber]

Describe your changes

• add a new calibration class FluxcalFactor for a flux cal factor to convert electrons to erg/(scm^2AA) plus corresponding error as single values (like KGain) which is to be generated for each filter.
• add functions to generate the calibration file.
• add the conversion in l4_to_tda plus error propagation.

Type of change

• New feature (non-breaking change which adds functionality)

Reference any relevant issues (don't forget the #)

#7 , #241

Checklist before requesting a review

• I have linted my code
• I have verified that all unit tests pass in a clean environment and added new unit tests, as needed
• I have verified that all docstrings are properly formatted and added new documentation, as needed
• I have filled out the Unit Test Definition Table on confluence, as needed

[JuergenSchreiber]

I made several assumptions:

• The data is already background subtracted.
• to generate the cal file I apply photutils tools. You can use either aperturePhotometry for circular apertures, where you can apply the fraction of the encircled energy in your aperture if you know the PSF or a 2D Gaussian extraction, just assuming that the PSF is Gaussian like.
• Up to now I use Ra/Dec and WCS to determine a rough pixel position of the point source, but there might already be an exact astrometric pixel position determined before in the pipeline already in the header.
• I had to update the photutils version in corgidrp requirements to >= 2.0.0 to get the Gaussian extraction

[maxwellmb]

Overall this is looking good to me, please see the few comments.

I've also reviewed the associated UT Tests in the DRP Test Definition page. Were the tests for "Tests to determine apparent magnitude in obs band" ever approved by anyone? I think the PR has been merged, right?

[JuergenSchreiber]

Overall this is looking good to me, please see the few comments.

I've also reviewed the associated UT Tests in the DRP Test Definition page. Were the tests for "Tests to determine apparent magnitude in obs band" ever approved by anyone? I think the PR has been merged, right?

The answers are No, not yet approved, and yes, has been merged

[maxwellmb]

Overall this is looking good to me, please see the few comments.
I've also reviewed the associated UT Tests in the DRP Test Definition page. Were the tests for "Tests to determine apparent magnitude in obs band" ever approved by anyone? I think the PR has been merged, right?

The answers are No, not yet approved, and yes, has been merged

Ok, great, thanks for letting me know. @semaphoreP did you look this over before accepting the PR, or should I still take a look?

[semaphoreP]

Overall this is looking good to me, please see the few comments.
I've also reviewed the associated UT Tests in the DRP Test Definition page. Were the tests for "Tests to determine apparent magnitude in obs band" ever approved by anyone? I think the PR has been merged, right?

The answers are No, not yet approved, and yes, has been merged

Ok, great, thanks for letting me know. @semaphoreP did you look this over before accepting the PR, or should I still take a look?

I haven't looked at the UT Test Definitions for this test, so if you can review them, that'd be great.