Data quality?

John Hayes:
You can stack the data you got to see how it looks but it won’t be as good as it could be under clear skies.  I personally toss out data taken under a thin over cast.

John

Same for me. The more I image, the more frames I tend to reject totally (as opposed to weighting them and using them). Normally I would not use that sort of frame at all these days.

Humidity not always bad, of course. At my remote site in California some of the best seeing often happens as the marine layer starts to intrude and that can give you fantastic seeing just before the transparency goes to zero (aka fog).  

Last night was even better since the marine layer came in but w/o fog and it resulted in the best seeing I have ever noted with the last part of the night mostly under an arcsec and a brief minimum recorded by the monitor at an incredible .51 arcsec...

I think it depends. I discard blatantly bad subs when I blink each morning. But you have to keep in perspective your average local conditions. I live in NYC, Bortle 8/9, few miles from a coastline, in the winter all the closely condensed houses are radiating heat off their roofs, conversely in the summer all the concrete sidewalks and paved street and radiating heat off from the daytime at night. 

When using apps like Astropheric and the likes - my seeing and transparency is below average probably 50-60% of the time (maybe more). So if I asked to filter out all subs taken in below average transparency conditions and then factor in my relatively small horizon I have to work with in my yard, factor in cloudy and rainy days I would basically only image 15 days a year. 

So long story short - blatantly bad subs I blink out and then after a few hours of data on each channel I’ll do a FBPP to see how the data is looking.