eleven day moon

The westward retreat of darkness continues to reveal the huge Oceanus Procellarum as a smooth area around mid-terminator. To its north, the narrow but long Mare Frigoris can now be seen in its entirety.

Within Procellarum, one Crisium width to the east and slightly above the centre of the terminator is Kepler, a class 1 crater with a developing ray system. In 1962, it was the subject of the first lunar geological survey. North from Kepler and adjacent to the terminator is class 1 Aristarchus. At full Moon this is the brightest object on the lunar surface. Copernicus, one Crisium length east from Kepler and first seen two nights ago, forms the third corner of a right-angle triangle which, as the Moon waxes, becomes curiously outlined by bright rays so neatly it might almost seem artificial.

Two Crisium lengths south of Kepler is the larger, class 5 Gassendi, a bright ring with a particularly convoluted floor. Its south wall has almost disappeared during the formation of the Mare Humorum, which it borders.

Roughly as far again south, and at a similar distance from the terminator, is Schiller. At first glance it appears foreshortened by the nearness of the limb, but comparison with its neighbours reveals the truth: it is elongated parallel with the limb by a factor of nearly 2.5 times.

Tycho, two Crisium widths north-west from the southern cusp, is now very bright, and a dark halo between the crater and its ray system begins to become apparent. At a similar distance from the southern cusp but close to and parallel with the terminator is a line of three conspicuous class 1 craters. The northernmost is Zucchius, then come fractionally larger Bettinus and Kircher.