I went to work this evening (the 21st) after the observations I described earlier, but I left the Intes OTA in the back of my car. When I got home -- about midnight -- I set up again, and I, too, had a look at Mars. The seeing was pretty good, and at 300x, I could see enough detail to orient myself on the map of the planet without having calculated the longitude of the central meridian beforehand. (It was about 55 degrees at half past midnight, PST). The planet looked very yellow, though, and I would say there was definitely a lot of haze or cloud in the Martian atmosphere -- detail vanished well before the limb. A red filter (Wratten 25A) improved contrast noticeably.

When I was about to go inside and ruin my dark adaptation anyway, I looked at the Moon. Schroter's valley was again prominent, and I could see the Aristarchus Rille VIII as well -- not bad, for so high a sun angle. While scanning the terminator, I came upon the Sirsalis Rille, whose broad curve in its southern half looked so dark and so uniformly narrow that I at first thought it was a filament of dust somewhere in the eyepiece.