JWSTWCSCorrector Used for Roman Data

[PaulHuwe]

When constructing a WCS object, this line:

stcal/src/stcal/tweakreg/tweakreg.py

Line 381 in d13f8df

def construct_wcs_corrector(

is called in the romancal pipeline:

https://github.com/spacetelescope/romancal/blob/a85994630bbde6656fa15922713ef8596e6f8248/romancal/tweakreg/tweakreg_step.py#L207-L212

and it produces roman files with JWST wcs variables in them, e.g.:

> af = asdf.open('r0000101001001001001_0001_wfi01_f158_cal.asdf')
> w = af['roman']['meta']['wcs']
> print(w)

From                   Transform                
---------- ----------------------------------------
  detector                            CompoundModel
      v2v3                           DVA_Correction
v2v3vacorr JWST tangent-plane linear correction. v1
  v2v3corr                                 v23tosky
     world                                     None

Is it appropriate that JWST and Roman have the same corrections? If so, the JWSTWCSCorrector should be generalized to both. If not, a ROMANWCSCorrector should be made.

[braingram]

Pinging @mcara on this one. The "JWST tangent-plane linear correction" string is coming from tweakwcs:
https://github.com/spacetelescope/tweakwcs/blob/369531ba4a87c1556ac922d3ee3b5d70c31be278/tweakwcs/correctors.py#L733

JWSTWCSCorrector is also implemented in tweakreg, which has no ROMANWCSCorrector. Is there any reason to have a different one for roman? If not, perhaps we rename this to something more generic like GWCSCorrector?

[mcara]

It is very specific to JWST and works for roman as well as long Roman has the same WCS structure as JWST. It is not a generic GWCS corrector. If the name is bothering anyone, you could subclass it in romancal (or stcal) as:

class RomanWCSCorrector(JWSTWCSCorrector):
    pass

We could rename it as STWCSCorrector but that would not be correct as it would not work for HST which uses FITSWCSCorrector.

I do not see what the issue is here. This was a known issue since the beginning.

[braingram]

I think the name is less of an issue. The presence of "JWST tangent-plane linear correction. v1" in roman files is more of an issue.

[mcara]

I see. I can add RomanWCSCorrector if you would like with a customized string.

[mcara]

Although, it is just a string. However, it is fixable.

[mcara]

See spacetelescope/tweakwcs#243

[mcara]

After tweakwcs PR is merged and a new version released, we will need to make changes to both stcal and romancal (and maybe jwst depending on how we decide to implement things) .