I have noticed recently that I get about an hour of good focus, a second of usable focus, and beyond that enough drift that I start to see donuts in dimmer small stars.
My setup: 205mm/1220mmfl newtonian F/6, Losmandy autoguided mount, QHY 163m mono camera, Baader MPCC coma corrector, 30s subs
My previous setup where I didn't notice this was the above except modded dslr, 2-3 minute subs
The seeing has also been better lately (usually terrible 2-3 a/s, now 1.4 a/s)
The scope goes out at 7PM, once the sun is behind the house, imaging starts at 10:30. Temps are 70s high, 50s low. Humidity low. I checked the focuser and it hadn't sagged.
1. Your shorter subs, highre rez camera, and better seeing has exposed something that was always there. Congratulations
2. One to two hours??!? I have to refocus every (fill in short time frame here).
3. Its a quirk of (netwonians, telescopes, imaging trains, pretty much all astrophotography)
4. Something else
If focus normally drifts over the night, does the focuser end up going slight inward or outward?
If autofusing is the answer, is there an option that won't break the bank and or isn't too heavy (I'm pushing the mount as is)? I use SGP if there is something that interfaces with that...I'm open to DIY and am pretty handy.
Edited by Maxtrixbass, 15 July 2020 - 01:10 PM.