by Marek Cichanski
Observed the moon from 19:15 PDT until about 21:15.
Intes-Micro Alter M603 on a CG-5 mount.
Tele Vue Nagler eyepieces: 16mm, 7mm, 5mm.
Started out in daylight, because I don't have a good observing spot to look at the moon when it starts to drop in the western sky. Had to catch it while it was still high. During the sunset-early twilight period, I used an orange filter to darken the sky background and make the details stand out from the blue haze. This was the same #21 filter that we were all jonesing for back around the time of the Mars opposition. It actually worked pretty well, and I think I'll try this trick again.
Seeing started out 4 of 5, and never got much worse than about 3 of 5. Nice!
Mare Serenitatis was mostly illuminated, with a nice 'grayscale gradient' across it. I always like that. The NE ramparts of the Montes Haemus were catching the sun brightly.
The classic area of 'Imbrium Sculpture' was on the terminator tonight, at the SW edge of Serenitatis. It had a very lineated appearance, particularly in the area between Menelaus and Julius Caesar. This is a great region to observe, given its significance in the recognition of large impact basins, from the time of G.K. Gilbert all the way up through the time of Shoemaker.
The south polar area was reasonably well librated and lit tonight. I think I identified Demonax and Scott clearly for the first time. Also Mutus, Manzinus, and Schomberger.
I decided to try to go after some of Charles Wood's 'Lunar 100' targets tonight. I suspect that I've already observed a fair percentage of them, but this was my first attempt to bring the list with me to the eyepiece. I started by picking out the crater Baco (L55), but its floor was mostly in shadow. Wood's S&T article mentions that it has an anomalously smooth floor, and that the surrounding plains are unusually flat. The floor was mostly in shadow, but what I could see looked flat, I'd say. And the plains around it did seem rather flat, which might be a bit unusual given how old they presumably are.
L18 is the 'collar' of dark patches at the southern edge of Serenitatis. This showed up nicely tonight. Saw a few parts of the Rimae Plinius, which are associated with one of these dark patches.
Might have just caught part of the Bessel ray (L41), but I think it will take slightly higher illumination to see it well.
In the north, Aristoteles and Eudoxus looked like bottomless black holes. Nice complex E rim on Aristoteles. In this light it appeared to have a 'detached block' like the rim of Plato. Marvelous 'pebbly ejecta' in this area, I could stare at it for hours.
Clefts and lineations on the rim of Julius Caesar suggest that it predates the Imbrium sculpture. Cool age relationship!
Barely made out the circular form of Lamont (L53), a possible buried crater. Wouldn't want the sun angle to be any higher. The domes Arago alpha and beta showed up nicely (L32).
Rima Ariadeus - fat as a goose! (L29). An almost perfectly straight cleft that transects numerous terrain features. Must have been due to some late-stage stretching of the crust. Perfect illumination -- NE wall was in shadow, while the SW rim was brightly lit.
At 20:55 PDT, I managed to FINALLY see the craters Armstrong, Aldrin, and Collins. Psyched! He shoots, he scores! These are L90. I got to feeling pretty sassy about bagging target #90. They had kicked my butt before, but with very careful examination of Rukl, long sessions of staring through the 7Nag+2x barlow (429x), I managed to positively and repeatedly identify them. That was really satisfying.
Hoped to see the Valentine dome, but it wasn't quite sunlit yet. Maybe next lunation.
Finished up with more full-disc views in the 16Nag. Life was very good.
Posted on sf-bay-tac Apr 25, 2004 23:30:03 PT
Converted by report.pm 1.1 Jul 10, 2004 19:30:48 PT