Mr_Cellophane autofocus works best for me if i roughly focus the stars so they are as small as possible and afterwards run the autofocus routine. Big bulbs do not help here and ASIAir will have a hard time finding any good reference, in which direction and how far it has to rotate the focuser.
Mr_Cellophane Why would it not just keep going until it was 100% perfect? How do I know how many times to run it?
Unfortunately, that is not how it works. Try to focus as good as you can manually then try autofocus again. Then it should not be necessary to run autofocus over and over again.
Mr_Cellophane Shouldn't this number be the exact same for each time I go out? Or is it normal to change?
Yes, it is normal that they change. For example, if temperature changes from session to session even if it is unnoticable by your bare eye. If it's warmer outside, your gear's material expands and the if it's colder outside, it will contract. This will affect the optical train and thus the focus point will be affected as well. Another aspect is the seeing: earth's atmosphere causes wobbly stars, sometimes, more sometimes less. This affects the focus position as well.
Olli
