SubframeSelector Algorithm that accounts for sky conditions?

[JST200]

Hi,

I don't know if this makes sense or or not, but is there a SubframeSelector algorithm that accounts for changing sky conditions (e.g. passing clouds, approaching dawn, etc.)

All the algorithms I've seen seem to focus on FWHM, Eccentry and SNRWeight. The one I am currently using, which came from Kayron Merciec's excellent Pre-processing tutorial (https://www.lightvortexastronomy.com/tutorial-pre-processing-calibrating-and-stacking-images-in-pixinsight.html), is:

(15*(1-(FWHM-FWHMMin)/(FWHMMax-FWHMMin)) + 15*(1-(Eccentricity-EccentricityMin)/(EccentricityMax-EccentricityMin)) + 20*(SNRWeight-SNRWeightMin)/(SNRWeightMax-SNRWeightMin))+50


This works well, but I've noticed that it can make an image that visually looks awful (over exposed due light pollution reflected off passing clouds or dawn light) can be weighted quite highly. I was wondering if it was worth adding a formula for "Stars", which seems to correlate reasonable well with the sky condition. Maybe something like:

(10*(1-(FWHM-FWHMMin)/(FWHMMax-FWHMMin)) + 10*(1-(Eccentricity-EccentricityMin)/(EccentricityMax-EccentricityMin)) + 15*(SNRWeight-SNRWeightMin)/(SNRWeightMax-SNRWeightMin) + 15*(Stars - StarsMin)/(StarsMax-StarsMin))+50

I have no idea if the weightings, or indeed any of it, make sense or not. So any thoughts, corrections or even "don't be daft"'s very welcome!

Thanks, Jim

[aworonow]

If you have one (I made one) that also has star count as a variable, then the conditions you mention could be covered by that. Also, using median brightness might figure in. My Excel spreadsheet (that interacts with the most recent PI subframeselector) allows you to select any four variables output from SS. Be glad to supply it, with instructions.
alex(at)faintlightphotography(dot)com

[JST200]

Hi Alex,

That's very kind of you. I'll send you an email now. 

Cheers, Jim