by Albert Highe
Richard Navarrete wrote:
I noticed that Starry Night shows a transit of Europa going on right now (6:45 p.m.) I stepped outside here in Oakland and the stars are twinkling pretty hard. Does anyone have good seeing tonight? It might actually be informative to start a log of seeing in various parts of the Bay Area. I'd be curious if the seeing were consistently better in certain cities.
I caught the beginning of transit with my 12.5" f/5 and could see the moon quite clearly against the limb of Jupiter at about 115X. Seeing was below average and the best magnification was probably limited to 150X. After a while it moved away from the limb and became almost impossible to see. It was just above (below) the dark band in a white section so contrast was very low. However, I was viewing out over my garage roof and the scope hadn't cooled down more than 15 minutes. In contrast, a few nights ago seeing easily supported >250X which is more typical. Its a very rare night that I can use much above that. About once a year I have gone to 500X with seconds of great still air.