twenty-four
day moon
The broad crescent Moon will be visible for much of morning through till after noon. It will transit around sunrise, so the best time to observe will be during the last hours of darkness.

Copernicus At its midpoint, the westward-advancing terminator has now reached class 1 Copernicus. To its north, the huge oval of the Mare Imbrium lies half in darkness. On the north-western shore of Imbrium, the Sinus Iridium is beautifully outlined by the crescent Jura Mountains, with small class 1 Bianchini elegantly positioned at the centre of the arc.

To the south-south-west of Copernicus at about two diameters, class 1 Reinhold shows well. At around twice the distance, the slightly smaller class 1 Lansberg appears as a dark circle with a bright rim and central peak.

Euclides & Riphaeus mountains Roughly one Humorum width south from here, the Riphaeus Mountains are bright. So too is the halo of ejecta around class 1 Euclides (Euclid), just to the west, and under this illumination the tiny dark circle of the crater itself may be seen.

Bullialdus Just over one Humorum length south-east from Euclides, class 1 Bullialdus is about to be overtaken by the terminator. South from here by about one Humorum width is a pair of similarly sized, dark floored class 5 craters, Campanus, to the west, and Mercator on the East. In this light the symmetry they showed when they first appeared two weeks ago is impaired.

A line drawn from Bullialdus to Mercator, extended by about one Humorum width, will reach Hainzel, a geologically complex structure of three amalgamated craters.