five day moon

To the north of the centre of the terminator, roughly two thirds of the Mare Tranquillitatis are now visible. Joined to its northern edge the eastern section of the oval Mare Serenitatis is now revealed, on the north-eastern shore of which is the ancient walled plain Posidonius. Within Serenitatis and roughly parallel with the terminator are the sinuous flow lines of the Dorsa Smirnov, a particularly strong system of wrinkle ridges.

Further south, the whole of the Mare Nectaris can now be seen. At its north-western end is the striking class 1 Theophilus, the northernmost of an imposing series of three ring mountains. On its south-western edge, it partly obliterates the much older, similarly sized class 3 Cyrillus. A little to the south lies a third, still more ancient crater of much the same size again - class 4 Catharina.

To the south of these, running parallel with the Mare Nectaris at a distance of about its width is the Altai Scarp, a 300 mile long and up to 2 mile high cliff, part of which is still in darkness. It faces to the east, and is therefore bright at the moment, but after the full moon will appear dark. At its south-eastern end is the class 1 crater Piccolomini.