Stubbs notes, July 22 2022

Not really enough detail here to tell where things stand.. 

near term goals:

construct a table that aggregates the airmass-dependent parameters a,b,c that come from the fits, with appropriate uncertainties, for all stars for all nights.

Then do consistency checks:

                 are the a and b values consistent for the oxygen line? Shouldn't depend on the star or the night
                 are the a and b values consistent with zero for all stars for all nights? 
                 etc. 

Identify instances of missing equivalent widths, to tell our friends who do these reductions. 

Make a list of bad-data instances, so we can screen them out of our analysis. 

stretch goals: 

1) 
Many of these stars have "known" spectra. They're called CALSPEC standards. See https://www.stsci.edu/hst/instrumentation/reference-data-for-calibration-and-tools/astronomical-catalogs/calspec

You could download the entire calspec catalog, and generate ASCII files of wavelength, flux. Note they use strange units. Our spectra are basically photons per sec per nm of wavelength but if Calspec uses energy units (likely ergs/nm/sec/cm^2) then need to convert to photon spectra (likely multiply by lambda). 
There is an overall vertical scaling we don't care about, only relative fluxes matter. 

Our observed spectra are the product of (star spectrum)*(atmos)*(instrumental response). 

If you spline the CALSPEC spectra onto same wavelength scale as our wavelength-calibrated spectra, fit our spectra as a function of airmass (the actual spectra, not the equivalent widths), extrapolate to zero airmass, and divide that by the known stellar spectrum we should recover the instrumental throughput function. 

2)
Using the spectra we have, for wavelengths less than 700 nm pick some clean regions and compute flux in 3-4 different intervals to investigate continuum reduction.