Sorry if this has been mentioned before, did a search couldn't find anything.
Under what conditions do I need to cool the mirror on my 10 inch Dob?
ie If theres say > 5 degree difference between the location the scope was stored and the viewing location?
How long do I need the run the fans for?
How can you Identify that the scope needs to be cooled? Is there anything you can see through the eye piece.
TIA for your help
Jjz