Ukert is a lunar impact crater that lies on a strip of rugged ground between Mare Vaporum to the north and Sinus Medii in the south. It was named after German historian Friedrich August Ukert. It is located to the north-northwest of the crater Triesnecker and northeast of the crater pair of Pallas and Murchison.
Mosaic of Lunar Orbiter 4 images (white spots are blemishes on original image)
Ukert crater, from GRAIL spacecraft
Ukert crater (right of center) is younger than the linear hills of Imbrium Sculpture that it overprints
Mare Imbrium is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision of a proto-planet during the Late Heavy Bombardment. Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it would have originally been when it first formed as a result of later events that have altered its surface.
The planned landing site for Chang'e 3 was Sinus Iridum. The actual landing took place on Mare Imbrium