/
QuadNotch Analysis 2022

QuadNotch Analysis 2022

Owned by Christopher Stubbs
Last updated: Aug 08, 2023

Figure is throughput in first (red) and second (blue) order for Semrock NF03-405-488-532-635E-50x50, adjusted for Rubin beam

data file of throughput, from vendor: SemrockQuadNotch.dat

Data used. 

Used Rubin TV to identify quad-notch filter and Ronchi 170 lines/mm grating. 

For 2021 Sept 8:

HUIT-FAS-MacBook-Stubbs:ut20210908 cstubbs$ cat FITSsummary.dat 

#   file                 MJDOBS       exptime      object     airmass     filter          grating         rotator         focus     median     maxnoise

---------------bias frames ---------------
AT_O_20210908_000004-  59465.8409  0  'slew_icrs'  0  BG40     empty_1 115.6725  0  5.61  9.8  
AT_O_20210908_000005-  59465.841  0  'slew_icrs'  0  BG40     empty_1 115.6726  0  6.19  9.8  
AT_O_20210908_000006-  59465.8411  0  'slew_icrs'  0  BG40     empty_1 115.6727  0  5.75  9.8  
AT_O_20210908_000007-  59465.8411  0  'slew_icrs'  0  BG40     empty_1 115.6727  0  6.26  9.8  
AT_O_20210908_000008-  59465.8412  0  'slew_icrs'  0  BG40     empty_1 115.6728  0  5.93  9.8  
AT_O_20210908_000009-  59465.8412  0  'slew_icrs'  0  BG40     empty_1 115.6728  0  5.81  9.8  
AT_O_20210908_000010-  59465.8413  0  'slew_icrs'  0  BG40     empty_1 115.6729  0  6.18  9.8  
AT_O_20210908_000011-  59465.8413  0  'slew_icrs'  0  BG40     empty_1 115.673  0  5.91  9.8  
AT_O_20210908_000012-  59465.8414  0  'slew_icrs'  0  BG40     empty_1 115.673  0  6.04  9.9  
AT_O_20210908_000013-  59465.8414  0  'slew_icrs'  0  BG40     empty_1 115.6731  0  5.75  9.9

--------------dispersed images ----------------- 

AT_O_20210908_000174-  59466.1155  30  'HD 185975'  1.839  quadnotch  ronchi170lpm 159.7795  0.037636  34.8  9.8  
AT_O_20210908_000175-  59466.116  30  'HD 185975'  1.839  quadnotch  ronchi170lpm 159.9684  0.037636  35.7  9.8  
AT_O_20210908_000193-  59466.1273  30  'HD 185975'  1.84  quadnotch  ronchi170lpm 164.2441  0.037636  34.1  9.8  
AT_O_20210908_000194-  59466.1278  30  'HD 185975'  1.84  quadnotch  ronchi170lpm 164.4335  0.037636  34.3  9.8  
AT_O_20210908_000212-  59466.1392  30  'HD 185975'  1.843  quadnotch  ronchi170lpm 168.7608  0.037636  36.1  9.8  
AT_O_20210908_000213-  59466.1397  30  'HD 185975'  1.843  quadnotch  ronchi170lpm 168.9519  0.037636  37  9.8  
AT_O_20210908_000236-  59466.162  30  'HD 185975'  1.85  quadnotch  ronchi170lpm 177.4017  0.033918  33.9  9.8  
AT_O_20210908_000237-  59466.1625  30  'HD 185975'  1.85  quadnotch  ronchi170lpm 177.5923  0.033918  35.1  9.8  
AT_O_20210908_000498-  59466.252  30  'HD 185975'  1.902  quadnotch  ronchi170lpm 211.5596  0.029994  27  9.8  
AT_O_20210908_000499-  59466.2525  30  'HD 185975'  1.903  quadnotch  ronchi170lpm 211.7513  0.029994  26.6  9.8  
AT_O_20210908_000514-  59466.2614  30  'HD 185975'  1.91  quadnotch  ronchi170lpm 215.1869  0.029994  25.9  9.8  
AT_O_20210908_000515-  59466.2619  30  'HD 185975'  1.91  quadnotch  ronchi170lpm 215.3785  0.029994  26.5  9.8  
AT_O_20210908_000622-  59466.324  30  'HD 185975'  1.964  quadnotch  ronchi170lpm 238.7461  0.0028539  34.4  9.8  
AT_O_20210908_000623-  59466.3245  30  'HD 185975'  1.965  quadnotch  ronchi170lpm 238.9358  0.0028539  33.9  9.8  
AT_O_20210908_000651-  59466.3476  15  'HD 14943'  1.073  quadnotch  ronchi170lpm 127.876  0.031635  14.6  9.8  
AT_O_20210908_000652-  59466.3479  15  'HD 14943'  1.074  quadnotch  ronchi170lpm 128.1684  0.031635  14  9.8  
AT_O_20210908_000727-  59466.358  15  'HD 14943'  1.08  quadnotch  ronchi170lpm 137.1976  0.031635  14.5  9.8  
AT_O_20210908_000728-  59466.3584  15  'HD 14943'  1.08  quadnotch  ronchi170lpm 137.4829  0.031635  14.5  9.8  
AT_O_20210908_000802-  59466.3901  30  'HD 185975'  2.028  quadnotch  ronchi170lpm 263.2932  0.011541  34.4  9.8  
AT_O_20210908_000803-  59466.3906  30  'HD 185975'  2.028  quadnotch  ronchi170lpm 263.4782  0.011541  33.6  9.8  
AT_O_20210908_000818-  59466.3987  30  'HD 185975'  2.036  quadnotch  ronchi170lpm 266.4849  0.011541  27.2  9.8  
AT_O_20210908_000819-  59466.3992  30  'HD 185975'  2.037  quadnotch  ronchi170lpm 266.6704  0.011541  27.4  9.8 
--------------------------------------------

Typical image, zoomed into spectrum:

Images were downloaded from SLAC repository, using method from Craig Lage:

The images are 16-segment FITS files, with names like 

AT_O_20210908_000009-R00S00.fits

used MATLAB code QuadnotchInjest.m (that's a link) to 

  • read in separate segments, amp by amp
  • compute and subtract row-by-row overscan
  • measure read noise and typical sky flux values
  • optional gain normalization (not done now) 
  • trim off 3 prescan pixels 
  • assemble full 16-amp FITS image as a single frame
  • wipe out bad column and other garbage regions on image
  • extract metadata from header (MJD, airmass, object ID, etc) 
  • optional y-binning (not used, didn't help)
  • write out full image. 

Note no multiplicative flat fielding applied. Dust spots will be an issue. 
No cosmic ray rejection
No 2-d bias subtraction. This is a nontrivial effect and needs to be dealt with properly. 
No correction for m=0 contamination from nearby stars

So Instrument Signature Removal (ISR) is pretty crude. 

Result is a directory of quadnotch plus Ronchi images. 

Photometry

source extractor doc: Guide2source_extractor.pdf

another reference: http://astroweb.cwru.edu/steven/Virgo/SExtractor.html 

Our goal is to assess whether photometry can be used to extract fluxes in the spectral regions of interest. Long term plan is to implement with DM/Rubin tools, but for now will use SourceExtractor.
Had to tweak the config file and convolution kernel to get what we want. Used 

gauss_2.5_5x5.conv

kernel for detection. 2022 Sept 7 version of SE config file: sex.config. 
Key parameters were min pixels above threshold, SNR threshold, and deblending parameters. 

Source extractor output parameter file: default.param

Run

sex -c sex.config AT_O_20210908_000727-.full.fits 

to get output file example: 

 

This is using the image check.fits that shows detected sources in a color that matches their catalog value, and MATLAB rectangle tool to overplot regions from source catalog test.cat

Red boxes indicate extent of SE sources, using min and max X and Y values. 

MATLAB rectangle tool used to draw these boxes- rectangle('Position',regions(6,:),'EdgeColor','r','LineWidth',3)
How to get the 'regions' array from Source Extractor output file: 

grep -v "#" test.cat | awk '{print $8,$9,($10-$8),($11-$9)}'. (computes lower corner and extent, for MATLAB rectangle command syntax). 

cut and paste that 4-element per object array into regions array in matlab. 

The sources we want are elongated, high flux, near 1800 in x, and oriented at 90 degrees (in SE convention). But theta is a signed angle and both +90 and -90 are valid for us. So to select sources of interest, do 

cat test.cat | grep -v "#" | sed 's/-//'  | awk '{if ($14 >= 85 && $15 >= 5 && $2<=2100 && $2>=1000) print $0'}  > cut.cat

(the grep selection cuts out comment lines, and the sed substitution takes abs(theta). The awk piece selects on angle and elongation and position in x). 

That produces a trimmed list of the 5 sources we want: 


Sept 11, 2022

Changed the program to do 2-d bias subtraction, since bias structure is too large to ignore. Still not making any multiplicative flat-fielding corrections, yet. 

We should use CBP with a slit and quartz lamp to get the kinds of flats we need, with the slit at the m=0 location of the star. 

After additional fussing around with Source Extractor parameters I obtained better outcomes. Changed the shape of the background computation to a rectangle, and adjusted deblending parameters and source detection thresholds. 

Computed flux ratios using FLUXAUTO which is apparently better behanved than FLUXBEST, according to SE for Dummies manual. 

Here is most recently used version of sex.config file: 20220911sex.config

Changed the program to put entire image FITS header on top of the source catalog file for that image.
Flux ratios, when they satisfy certain quality criteria,

Example of flux ratios at 405/488 488/488 532/488 635/488 added onto FITSsummary.dat by hand, such that

cstubbs$ awk '{printf("%s \t %s \t %s \t %s \t %s \t %s \t %s \t %s \t %s \t %s  \n"), $1, $2, $4, $5,$6, $12, $13, $14, $15, $16, $17}' FITSsummary.dat  | grep -v "#" | grep 185975

produces 


and 


Summary of HD 185975 : 185975.dat
Summary of HD 14943  : 14943.dat





MATLAB code, 20220911: QuadnotchInjestAndAnalyze.m


September 24, 2022.

Eske found a listing of all quadnotch data taken to date. Selecting out images of pole star HD 185075. These have the advantage of being at nearly fixed airmass, so we can look at temporal evolution with fixed stellar SED. 

2020021900256 quadnotch1~ronchi90lpmm HD 185975 2.14923808304389
2020022000287 quadnotch1~ronchi90lpmm HD 185975 2.14808580284342
2020022000314 quadnotch1~ronchi90lpmm HD 185975 2.14047683039539
2020022000319 quadnotch1~ronchi90lpmm HD 185975 2.13546236403688
2020022000321 quadnotch1~ronchi90lpmm HD 185975 2.13440188692662
2020022000323 quadnotch1~ronchi90lpmm HD 185975 2.1329698330371
2020022000325 quadnotch1~ronchi90lpmm HD 185975 2.13149993021006
2020022000463 quadnotch1~ronchi90lpmm HD 185975 2.02746700017131
2020022000483 quadnotch1~ronchi90lpmm HD 185975 1.99866064021964
2020022100548 quadnotch1~ronchi90lpmm HD 185975 2.12254418512916
2020022100553 quadnotch1~ronchi90lpmm HD 185975 2.11714111531212
2020022100554 quadnotch1~ronchi90lpmm HD 185975 2.1168960594739
2020022100555 quadnotch1~ronchi90lpmm HD 185975 2.11647147226023
2020022100556 quadnotch1~ronchi90lpmm HD 185975 2.11625452459681
2020022100559 quadnotch1~ronchi90lpmm HD 185975 2.11460502860103
2020022100692 quadnotch1~ronchi90lpmm HD 185975 2.02642003037661
2020022100706 quadnotch1~ronchi90lpmm HD 185975 1.99438440238076
2020022100738 quadnotch1~ronchi90lpmm HD 185975 1.97916473830115
2020022100756 quadnotch1~ronchi90lpmm HD 185975 1.96840371352498
2020022100783 quadnotch1~ronchi90lpmm HD 185975 1.95377450516058
2020031200316 quadnotch1~ronchi90lpmm HD 185975 2.0233460886104
2020031200329 quadnotch1~ronchi90lpmm HD 185975 2.01495899047431
2021012000318 quadnotch1~ronchi90lpmm HD 185975 2.11696118658571
2021012100734 quadnotch1~ronchi90lpmm HD 185975 2.09174582871705
2021012100742 quadnotch1~ronchi90lpmm HD 185975 2.09676204574036
2021012100750 quadnotch1~ronchi90lpmm HD 185975 2.10007468693319
2021012100778 quadnotch1~ronchi90lpmm HD 185975 2.12132922099186
2021012100794 quadnotch1~ronchi90lpmm HD 185975 2.12971607264433

Using Craig Lage's back-door FITS file access trick: 


went here:

https://usdf-rsp.slac.stanford.edu/


chose notebooks in the cloud.

Downloaded the list of polar-star images above. 

Tried running Source Extractor on the Ronchi 90 line/mm grating images but spectra are too blended for it to work well. 


PPT:

PseudoAerosols20230322.pptx






Copyright © 2024 The President and Fellows of Harvard College * Accessibility * Support * Request Access * Terms of Use