[Quark (Trevor)]

Impressive result for the alt Stuart, might be worth a try running the fan for 2 or 3 hours prior to imaging and then turning it off about 5 minutes prior to capturing data as a comparison to capturing data with it running.

Of course, just using a fan to circulate ambient air over your primary, will never result in your mirror achieving ambient temperature. Your mirror is a quite large heat sink and its temperature will always lag behind ambient as the ambient drops through the night. The only way around that is to use an active cooling system that will circulate air at below ambient over your mirror.

When I first was made aware of this by Bird, initially I had doubts but having built my own peltier cooler and seen the difference it can make, particularly in good seeing, I have become a convert.

Have attached a link to Birds original work on this subject, note that from the bottom of his first page is a link to his ongoing testing.

http://www.acquerra.com.au/astro/cooling/

Regards
Trevor