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NSG frustration, and better understanding of SNR relationship to FWHM (two things, semi related...)
Following the Fundamentals tutorial...
NSG does not generate the "Photometry" previews consistently, I cannot find any rhyme or reason to elaborate beyond that. It works consistently for the Reference Image, but not others, and frankly only generates the Photometry result occasionally. It detects stars fine. I have repeated this process a half dozen times now from scratch with the same result, trying different subs. (This included restarting PI since I have had a few issues recently where PI glitched and needed restarting...) It feels like a glitchy script, but I am sure it is something I am missing. Do subs need to be registered first maybe? This is not mentioned in the Fundamentals tutorial if so...
The first run through with NSG, (I thought I had it generating Photometry results, but maybe not), it produced several subs that we WAY worse looking than the starting file.
I cannot find the original documentation referenced in the script's header "Prerequisites...", but this could be because of my unfamiliarity with PI documentation. I did do a Google search and still couldn't find it.
And, tangentially related but very important to me understanding whether NSG is worth the time and hassle, I am hoping for a good resource on the relationship between SNR and FWHM/seeing conditions, basically something to explain how the various factors used in weighting, (or culling), images may be related, what causes them, etc...
-Anthony
NSG does not generate the "Photometry" previews consistently, I cannot find any rhyme or reason to elaborate beyond that. It works consistently for the Reference Image, but not others, and frankly only generates the Photometry result occasionally. It detects stars fine. I have repeated this process a half dozen times now from scratch with the same result, trying different subs. (This included restarting PI since I have had a few issues recently where PI glitched and needed restarting...) It feels like a glitchy script, but I am sure it is something I am missing. Do subs need to be registered first maybe? This is not mentioned in the Fundamentals tutorial if so...
The first run through with NSG, (I thought I had it generating Photometry results, but maybe not), it produced several subs that we WAY worse looking than the starting file.
I cannot find the original documentation referenced in the script's header "Prerequisites...", but this could be because of my unfamiliarity with PI documentation. I did do a Google search and still couldn't find it.
And, tangentially related but very important to me understanding whether NSG is worth the time and hassle, I am hoping for a good resource on the relationship between SNR and FWHM/seeing conditions, basically something to explain how the various factors used in weighting, (or culling), images may be related, what causes them, etc...
-Anthony
Comments
My second, semi related, question remains. Some direction to resources on the causes, relationships and implications of weighting factors would be much appreciated.
In part, this question stems from my observation that SNR Weight and FWHM generated by WBPP seem to have an inverse relationship when I am looking at them in Subframe Selector, with the low FWHM subs being obviously much better than the high SNR Weight frames. Maybe this is what is discussed in the NSG tutorial video?
So to re-state that thought, FWHM may not be the best way to weight frames, but it can be useful, I would think, to cull outlier subs or evenings not conducive to long FL/high resolution imaging.
Is that a sound premise do you think?
This is why I am working through your recommendation to use NSG.
Thanks!
FYI, I got NSG to work and it produced an exceptional result.
Thanks!