The Sun Solar System: the Moon Planets observing logs

May 12 2005, Lunar-observing log: Western Mare Crisium

Two ghost craters and two old capes (Rukl 37 and 26).

Tonight I observed the Moon together with Leo, a fellow observer who lives just down the road. This was the first time we had the chance to observe the Moon with his new telescope, a 10-inch TAL Klevtzov Cassegrain. We started around 20.00 hrs UT. The Moon was still high above in the sky, but we immediately noticed that the seeing was bad. There was a lot of turbulence in the air, but we still managed to shoot a few pictures and do some observing.

Last night the four big craters Langrenus, Vendelinus, Petavius and Furnerius stole the show while lying near the terminator. Today we still could detect the Rimae Petavius very easily, but what I liked most was Mare Crisium. The mountains around Mare Crisium, where beautifully lit. These mountains probably form the second ring of the Crisium impact basin, while the wrinkled ridges in Mare Crisium probably form the first basin ring. On the western rim of Mare Crisium some interesting features could be detected.

First there where the two ghost craters, Yerkes and Lick. Both craters are about 35 km in diameter. The eastern rim of Yerkes, a flooded crater. Yerkes is almost completely covered by the Mare lava. The lava flooded floor has exactly the same colour as the surrounding Mare Crisium. To the north, Yerkes is connected to a small crater Yerkes E by a narrow ridge. More to the south lies Lick, another lava flooded crater.

To the northwest of Yerkes lie Cape Olivium and Cape Lavinium. situated opposite each other. According to the Rukl Atlas the names are old, unofficial and little used. In 1953 O'Neill, chief editor of the New York Herald Tribune thought he discovered a "natural bridge" of 2km wide and about 30 km long, connecting Cape Olivium and Cape Lavinium. The shadow he saw was not produced by a bridge between the two capes, but by the curved rims of two craters to the west, Proclus P and Glaisher X.

Mare Crisium area

Around 22.00 hours UT the seeing got even worse. With a last glimpse at the Moon in the western sky, accompanied by Castor, Pollux and Saturn, we packed up for the night.

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