Kl/update lss traces

[astronomyk]

As part of to #167, here are the new FITS files for the LSS traces based on the optical model from 2023-06-20 that was used for manufacturing the LSS grisms.

[teutoburg]

I'm not sure I understand the commit history here. Why does this go back 2 years? I checked out a local version of this branch and it let me rebase onto dev_master without any conflicts. Is there a specific reason why the commit history is what it is here? If not, I can push the rebased version to this PR if you want.

[teutoburg]

Also now merging this will close #167, but this PR is only one of two parts there. So I suggest waiting with this merge until the other task is finished, which should be today anyway...

[hugobuddel]

This broke the METIS notebooks:

• https://github.com/AstarVienna/irdb/actions/runs/8615086139
• https://github.com/AstarVienna/ScopeSim_Data/actions/runs/8626248477/job/23644148710

Please run the notebooks before you merge something big like this @astronomyk

[hugobuddel]

The notebooks also run when you start the CI on github manually, so there is no reason to not run them.

[hugobuddel]

Also note that while TRACE_LSS_L.fits is replaced, with the original being renamed to TRACE_LSS_L_old.fits, it was TRACE_LSS_L_sci.fits that was used as default trace file. Now the default is the new TRACE_LSS_L.fits. I think this is confusing. Is the TRACE_LSS_L_sci.fits also old? I think old files should be removed; they can be found in the history if necessary.

Comparing TRACE_LSS_L_sci.fits with the new TRACE_LSS_L.fits, it can be seen that the main difference is that these header keywords only appear in TRACE_LSS_L_sci.fits: {'CTYPE1', 'CRVAL1', 'CRPIX2', 'MJDREF', 'CRPIX1', 'CDELT2', 'WCSAXES', 'CRVAL2', 'LATPOLE', 'CUNIT2', 'CTYPE2', 'CDELT1', 'CUNIT1'}. The other differences in the headers is expected, like dates and such.

TRACE_LSS_L_sci.fits is still in the repository, so we could 'fix' the notebook by just explicitly referencing that in !OBS.trace_file, but that seems kinda wrong, since I expect that file to be outdated too.

It is also concerning that the TRACE_LSS_L_sci.fits a the old TRACE_LSS_L.fits could not be used interchangeably.

I don't know where these headers came from. I suppose the best solution would be to add similar headers to the new trace maps. Maybe we can just copy them over? I'm assuming here that the overal structure of the FITS file has not changed.

[hugobuddel]

The notebook says

Before showing the background subtracted spectra, we convert the pixel numbers to wavelength and spatial position along the slit. This is possible because the current version of Scopesim/METIS by default uses perfectly linear mapping of the spectra onto the detector. The WCS keywords to use are in metis['spectral_traces'].meta.

I have not inspected the files, so I don't know whether the new files also use a "perfectly linear mapping". It seems so, but maybe the numbers are not the same anymore. The traces seem more compact.

[teutoburg]

I think old files should be removed; they can be found in the history if necessary.

agree 👍