I copied the subject line from the earlier message and saw my mistake; kind of embarrassing that I called it "Mt. Hamilton Observatory". Forgive me, I do know that it's Lick Observatory on Mt. Hamilton.

Anyway, I mentioned it was hard to get that shot, but I didn't explain that the lighting conditions are so critical that the observatory seems to literally disappear and reappear at unpredictable times. Took me a while to catch on to why, and before I did I was doubting my eyes or my sanity. A little while ago I looked over and happened to catch it disappearing, and because it's a windy day and lighting is changing rapidly, I was able to set up my camera take two frames within a minute of each other catching it in the act. It's clear what's going on with telephoto magnification, but to the naked eye it looks like a disappearing act.