Alphonsus (crater)

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Alphonsus is a lunar crater 117 km in diameter on the eastern edge of the Mare Nubium, immediately south of the crater Ptolemaeus.

The walls of the crater rise up to 3 km above the crater floor. A north-south direction extending 15 km wide in the center and one kilometer high back divides the crater floor. On the largely flat crater floor, a system of lunar grooves Rimae Alphonsus runs.

The astronomer Nikolai Alexandrovich Kozyrev discovered in 1958, Alphonsus transient lunar phenomenon, a reddish concealment, the cause may lie in escaping from the lunar rocks molecular carbon and ultraviolet radiation from the sun.