Hi William, et al; It is interesting that we get so few evenings of really great seeing and yet, those stand out as some truly memorable nights. As Tom mentioned the seeing is generally about 2 arcseconds down on the desert floor. So the SAC sites: Flatiron, Sentinel, our old sites: Table Mesa and Buckeye all usually provided seeing around that value. Of course they were often much worse. But, every once in a while, they steadied down and got superb for a couple of hours; everyone observing for that time got to see just how good their telescope could perform at high power and how much detail they could see when things were good. Because my backyard observatory gets more use, I have been fortunate enough to have several evenings of good seeing there, also. I can always tell when powers above 250X are actually useful, then the seeing is good. This is generally during twilight, as I recently reported and it generally lasts 15 to 20 minutes. Several of the best times of steady seeing have been when there was a thin cloud deck. We set up the scopes under pretty clear skies and some cirrus clouds came in and some bullheaded soul kept observing....then he called over to us to say "hey, get on Jupiter, it is really GREAT!". Many of the times that I have had both good seeing and good transparency have been after midnight. The seeing has had time to steady down and the transparency is still clear. Again, those are superb and memorable nights. It feels like the Milky Way is just past your finger tips. Hoping for more of that; Steve Coe Author "Deep Sky Observing--The Astronomical Tourist" Saguaro Astronomy Club website www.saguaroastro.org -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.