Passive mirror cooling

[DavidU]

I did a little investigating and it seems that if the back of a Newt mirror is painted flat black it should radiate about 3x the infra-red radiation than standard bare ground glass.
I will try to get 2 glass blanks and run some tests.
Any thoughts?

[kinetic]

Dave,

only that the paint might act as a thermal barrier to the cool down
and maybe slow the heat transfer?:shrug:

I have always found that on the BEST seeing nights when I did webcam
planetary years ago, and more recently with monochrome hi-res deep sky,
the best results were from non-fan assisted cool down and only after a
few hours of just leaving the dome open.
Trevor Barry AKA Quark has reported good results with a peltier assisted
cool down mirror cell and his planetary results stand as good evidence.
I think as long as your mirror is as close to ambient as possible.....and
ambient isn't dropping like the proverbial brick, then seeing and
technique are the only thing holding you back.

FWIW

Steve

[DavidU]

Steve, I found that there are 2 types of paint that assist in heat transfer.
These are commonly used in the automotive & heater manufacture.
Anyway, just a thought at this stage.