Twenty-Six Day Old Moon‡

The Moon appears as a crescent in the eastern sky today. It does not rise until well after midnight, and transits around 10 am, so that the best time to observe will be during the very last hours of darkness, before the dawn.

The Sun's overhead light is now becoming far away from the side of the Moon turned towards the Earth, and as a result relief of features is low, and the surface appears flatter than it actually is. Contrast between the somewhat dark Maria and the bright uplands is weak.


Key Features to Observe Tonight

About midway from the northern cusp to the equator is Aristarchus, which now stands out due to its dark-shadowed interior rather than its brilliant ejecta. The indistinct flat area to south of it and stretching to the limb is the Oceanus Procellarum.

Grimaldi, just south of the lunar equator, still shows up nicely as a darker patch, despite the generally low contrast tonight. Southeast of Grimaldi by about twice its diameter is a contrasting pair of craters: the light floored Hansteen and the dark-floored Billy. Billy is the easier of the two to spot, and lies farther from Grimaldi.

To the south at almost the same distance again, is Mersenius, a larger crater, unusual for its convex floor. Continuing south is the huge walled plain Schickard. This is another crater with a slightly convex floor.

Just southeast of Schickard is the so called "lunar footprint" feature created by the two craters: Nasmyth (the heel) and Phocylides (the sole).

Finally, very close to the terminator, is a set of similar craters: Zucchius, Bettinus, and Kircher (in order from north to south).


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