>> ...do some scouting when I know exactly where the Lowell site is located. The ClearSkyClock page has a link showing a patch of the 7.5-minute topo map, which you can zoom in/out; the default cut-out shows the settlement and some of the surroundings. >> I'm not sure what 0".84 seeing looks like... 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. \Brian -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.