Ptolemaeus (lunar crater)

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The lunar crater Ptolemaeus - a sprawling, 150 km major Wall level - lies almost in the center of the visible from the earth moon half. He is in a weak cratered region between the planes sinus Medii and Mare Nubium.

Together with the lunar craters Alphonsus and Arzachel it forms a kind of triumvirate in the center of the lunar disc. The strikingly smooth wall level of Ptolemy follows exactly the moon curvature and is completely filled by lava, but has no central peak. The crater rim rises above the level about 2400 m high. Generated Inside subsequent impacts still a number of smaller craters, of which 9 km in diameter is lower in the most visible and was named Ammonius. Just north of it is when the sun is low (see Terminator ) to recognize a strongly eroded "ghost craters ".

Ptolemy is the oldest craters in this region. His level is partially covered by ejection of the impact, which gave rise to the crater Alphonsus. The edges of Ptolemaeus and Alphonsus be cut by a striking system of parallel edges and ditches which is called " Imbrium sculpture " because it radiates from the Mare Imbrium.