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LSSTDESC / imSim

GalSim based Rubin Observatory image simulation package
https://lsstdesc.org/imSim
BSD 3-Clause "New" or "Revised" License
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Enhance sky glow and other sky structure in the ESO model. #82

Open cwwalter opened 7 years ago

cwwalter commented 7 years ago

Currently the sky glow model by @yoachim in

https://github.com/lsst/sims_skybrightness

based on the ESO model with twilight addition includes sky glow but it does not have any structure. It is just an overall brightness level adjustment.

Brian Stalder (@bstalder) points us to the work he did with Chris Stubbs to measure the variation at the LSST site as outlined in this paper:

https://arxiv.org/pdf/1002.3637.pdf

Note that the PhoSim model is based on 2MASS measurements in the IR as documented here:

Adams & Skrutskie 1996, 2MASS Airglow Experiment Final Report.

http://faculty.virginia.edu/skrutskie/airglow/airglow.html

Sky glow variation along with other spatial varying effects should be added to the model. This is also related to #12 which is for adding clouds.

bstalder commented 7 years ago

Unfortunately we didn't make a power spectrum of the spatial variation, but probably tracks the J, H since they are both derived from OH excitation. Our measured y band p-p variation was about 4%, but the overall background level varied by more than a factor of 2 over a few nights.

yoachim commented 7 years ago

It would be an interesting exercise to grab DECAM and/or HSC data and do ISR, mask sources, and then look at residuals (and power spectrum) compared to the smooth sky model.

cwwalter commented 4 years ago

@RobertLuptonTheGood points to this paper

https://www.aanda.org/articles/aa/abs/2014/07/aa23908-14/aa23908-14.html

For a nice discussion of sky glow variability.