Thanks for the explanations guys. I have fans mounted on the C11 to cool it down. It's stored indoors in my office and I have aircon running so I'd say by the time I take it out it's pretty close to the temp I get at night.
Anthony, my ED80 is painted dark grey, same as the C11. Interesting about the white paint. Who would have thought. I always wondered why your newt tube was bare - now I know.
Wondering if covering the tube with some kind of insulation would help with dew prevention. I recall Monte had his FSQ106 wrapped into some thermal fabric embedded with nichrome wire to keep both ends of the tube at the same temp and avoid contraction.
I think Greg Bradley mentioned something about wrapping the tube in rags too to minimise heat loss.
PS: So just I'm clear in my rambling, my problem is not with cooling down the optics, quite the opposite. I need to keep the optics just above the dew point. At the moment all my stuff is going cold too quick. I have no problems with tube current. I took care of that.
