I agree. The 8" took a long time to cool down in relation to my 6" TMB but once there, it was fine, When we had extreme drops in temperature that same issue you describe above reared its head but never to the extreme you describe in your post.

Of course, I was dealing with a lot smaller volume of glass. I just ran the numbers on the overall difference in actual glass area between my 8" and Markus' 12" and the increase between these two optics is staggering, recognizing the the increase of 4" in diameter is not a true measure of the increase the size or ability of the optic. The superior light gathering ability is a result of a whooping increase in the surface area of the elements, which is more akin to a geometric increase. The vastly larger surface area is what, in theory, should give you much enhanced views. But those now huge triple elements are going to take a LOOOONNNNG time to settle down and I have no doubt Markus had a real beast on his hands in the conditions you describe. Dave