Six Day Old Moon‡

The Crescent Moon continues to rise earlier in the day. It will now be visible all afternoon and up until late at night. Transiting before sunset, the best time to observe will be during the first hours of darkness, while it is highest in the sky and darkness provides greatest contrast.


Key Features to Observe Tonight

The eastern end of the Mare Frigoris in the far north comes into view tonight. This mare is a long, narrow plain which requires six nights for the terminator to cross and completely appear from the nightside. To the south is the conspicuous ring mountain crater Aristotle, and directly south from it, a slightly smaller companion, Eudoxus.

Most of the Mare Serenitatis is visible tonight. Compare the wrinkle ridges Dorsum Azara and Smirmov on its floor over the next few nights as the lighting and contrast changes. On the northwestern edge of Mare Serenitatis lies the great Caucasus Mountains with their towering peaks. This is a good night for observing them, as they lie very close to the terminator.

Just north of the equator, all of Mare Tranquillitatis is visible tonight. Pliny appears as a bright crater alone against the dark surface where the two maria meet. Dawes is the much smaller crater to its east. About twice as far to the west is Menelaus, which as the Full Moon approaches will become one of its brighter points. Although it is small, it is clear and well defined.

Mare Tranquillitatis was the landing site for the Apollo 11 mission. The landing module from which Neil Armstrong made man's small step in 1969 sits on the surface in the southern area. Three small craters here are named in honor of the astronauts (Armstrong, Aldrin and Collins). These are the only nearside features which break the convention of naming features posthumously. The craters may only be seen with larger telescopes, as they are under three miles across. Unfortunately, the landing module base itself is much too small to be seen with any Earth-based telescopes.

Due west of Mare Tranquillitatis, in the uplands, the fascinating Rima Ariadaeus runs northwest. This cleft in the Moon's surface is wide enough to show well even against the rough backdrop of the uplands. Southeast from it lies the crater Delambre, very conspicuous for its modest size. Southeast from here, just before Mare Nectaris are several craters which, like last night, make excellent observing. The northernmost is Theophilus, which, together with its similarly sized but progressively older southwesterly neighbors, Cyrillus and Catharina, can provide many hours of observing pleasure for avid lunar observers.Southwest of Catharina a good distance away, near the terminator, lies Maurolycus, prominent even in the heavily impacted landscape of the Moon's southern hemisphere.


‡with permission from Lunar Discoverer User's Manual by Robert Duvall, 2013