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Sept 1, 2022

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It wants Ozone content as gm/cm^2 and we have it in Dobson units. Wikipedia says 1 DU is 2.69×10²⁰ molecules per meter squared.
Molecular weight of O_3^16 is 47.992 gm/mole. One mole is 6.023E23 molecules. One square meter is 1E4 cm^2. So: 

1 DU = 2.69E20 molecules/m^2 * (1m^2/1e4 cm^2) * ( 47.992 gm/mole) * (1 mole/6.023E23 molecules) = 2.1434e-06 gm/cm^2

so to get O3 in gm/cm^2 do (DU*2.1434e-06) 

250 DU = 5.3586e-04 gm/cm^2

PWV is in mm, collapsing entire column density into some depth of liquid. MODTRAN6 wants gm/cm^2 of H2O. Density of water is 1 gm/cc, so 1 cm of water is 1 gm/cc. 
So for this the conversion is 10 mm PWV → 1 gm/cc. Typical Pachon PWV is a few mm. Let's use a default 5mm PWV which corresponds to 0.5 gm/cm^2. 

Set up point-to-point geometry from LSST elevation to 80 km, straight up.

Data go to ~/MODTRAN6

rename .tp7 output files with X.XX***.dat where X.XX is airmass to 3 sig figures
Matlab code ReadModtran6.m will then read in and act on these files. Need at least 4 of them. 

The ***.psc output file is really simple; nm, T in two columns. 

Default Atmosphere at zenith

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 Images from March 16 2023 seq num 477 has a star with nice stellar atmosphere features. HD 73495 = Eta Pyxidis HR 3420. HD 73495. HIP 42334 is an A0V star.
Spectrum from RubinTV is

Image Modified

Copied images from 20230316 to local disk on laptop. Need to include bias frames as well as images of interest. Note that dispersion depends critically on disperser-to-CCD spacing so we should solve for it each time. 
Note apparent m=0 stellar contamination at blue end of band3. We need to either subtract those out or median-filter with rotations. 

Balmer lines are at

486.135
434.047
410.173
397.007
388.906
383.540

Downloaded seqnums
477
745-755 bias frames

Ran InjestAndAnalyze.m to create bias frames and full frame debiased images. 

Ran Specexam2.m on frame AT_O_20230316_000477.full.debias.fits. m=0 star centroid is row 300.4 and col 1737.1

zoom on spectrum at absorption lines

Image Modified

March 21, 2023

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do geographical search on latitude -30:14:40.68 longitude -70:44:57.90; = -30.245, -70.75

Well, that didn't work so well. Try this: 
https://www.esrl.noaa.gov/gmd/grad/neubrew/SatO3DataTimeSeries.jsp 

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If observed - model is negative, then model extinction is > observed. Difference between 570 nm and 380 nm is 0.75 percent. We see about 1% 
So this is indeed possibly a real discrepancy, and our measurement might not be the culprit. 

How about aerosols? Take our band centers as 373,  445, 508, 575. Patat aerosol estimate from 2011 would imply (see figure below) 

Image Added

Image Added