Brian, > Consider that the Airy disc of a 6-inch aperture is 0".85. > So the usual thing with that aperture would be to see "no seeing" at the > Happy Jack site; presumably Pickering 10 on average for that aperture. > If you get some of that "first quartile" seeing, then you wouldn't > see any image motion with a diffraction-limited 10-inch telescope. This sounds terrific! Observing in a 6-8 mph breeze (as per Brian's prior note) will be painful especially if it is cold (as a desert dweller I regard cold as any temp below 80F :)) but maybe we can come up with a wind buffer. Don't know off hand how one could make a portable windbreak that could stand up to 6-8 mph winds, which is pretty stiff, but I will be thinking. Thanks again Brian, this is really great news. Regards Bill Wood -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.