Add diagnostics to headers

[awhoward]

This Issue is to organize several notes about diagnostic information that @awhoward plans to add to the headers. Note that these keywords should also be documented here.

• ✓ Dark noise (see https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/pull/729)
• ✓ Read noise from the overscan region. @RussLaher - is this already in the headers or just the DB?
• ✓ SNR at several wavelengths (done, but needs to be documented - See https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/issues/514).
• ✓ Cumulative Exposure Meter counts (see https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/issues/535)
• ✓ SCI/SKY flux ratio estimate of the main spectrometer from exposure meter (see analyze_em.py).
• ✓ Seeing estimate from a fit to the guider image (see analyze_guider.py).
• ✓ Guiding performance summaries (x_rms and y_rms at a minimum; other diagnostics, too? see analyze_guider.py).
• ✓ CCD read speed (see kpf_parse.py)
• ✓ lunar separation and solar altitude (see analyze_guider.py).
• ✓ Flux ratios between slices (see https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/issues/351).
• ✓ Order-to-order flux ratios (see https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/issues/394).
• order trace drift? (see https://github.com/Keck-DataReductionPipelines/KPF-Pipeline/issues/352)
• instrument drift (is this the cal RV?).

[RussLaher]

Read-noise keywords are now included in the PRIMARY header of the 2D FITS files. E.g., KP.20231121.06358.42_2D.fits:

RNGREEN1= 4.85283 / Instantaneous GREEN_AMP1 read noise [electrons] RNGREEN2= 4.14966 / Instantaneous GREEN_AMP2 read noise [electrons] RNRED1 = 4.0376 / Instantaneous RED_AMP1 read noise [electrons] RNRED2 = 4.12717 / Instantaneous RED_AMP2 read noise [electrons] GREENTRT= 46.804 / GREEN chip total read time [seconds] REDTRT = 46.839 / RED chip total read time [seconds] READSPED= 'regular ' / Categorization of read speed

[awhoward]

Thanks, Russ. I'll add those headers to the documentation here: https://kpf-pipeline.readthedocs.io/en/docs-pipeline-info/info/data_format.html

[awhoward]

@RussLaher, are GREEN_AMP3 and GREEN_AMP4 read noise values computed if those amplifiers are used (for fast read mode)? (And the same for RED.)

[RussLaher]

Yes, indeed. Read noise is computed for all amplifiers present in a given L0 FITS file (except for CA_HK).