four day
The best time to observe the Moon is during the early hours of darkness, when it will appear as a crescent in the western sky.

Mare Crisium The Mare Fecunditatis is fully revealed, south of the midpoint of the terminator, and the contrast between the Mare Crisium and its bright surrounding region is becoming more pronounced. At a latitude midway between these two seas, the eastern end of the Mare Tranquillitatis has appeared, whilst south along the terminator and level with the southern edge of the Mare Fecunditatis is the eastern half of the smaller Mare Nectaris.

Cauchy Other new landmarks include class 5 Taruntius, a bright ring rising from the darkness where Fecunditatis meets Tranquillitatis. To the north-west of Taruntius by a little under one Crisium width is Cauchy, a small, sharp circle in Tranquillitatis. It lies between a pair of north-west to south-east diagonal lines - the northern one being Rimae Cauchy, a pair of adjoining rilles or shallow clefts, and the southern one being Rupes Cauchy, a south-facing fault which shows dark at the moment but bright under the setting sun.

Metius, Fabricius and Janssen On the western edge of Fecunditatis, about one Crisium length from Taruntius, is the broken ring of class 5 Gutenberg. From here, the Pyrenees Mountains run due south for about one Crisium width, almost reaching class 1 Santbech. A further two Crisium widths south is an interesting cluster of craters: Metius and Fabricius, both class 2, are about 50 miles across and form a figure 8. The southern partner, Fabricius, is inside the extremely ancient walled plain Janssen.

On the western side of Crisium is a bright region, at the centre of which is class 1 Proclus. This area will continue to brighten still further over the coming nights.

To the north of the Mare Crisium by about twice its length is the distinctive dark-floored oval of class 5 Endymion, to the south-west of which, by a couple of times its width, is a distinctive pair: class 5 Atlas and to its west class 1 Hercules.