Aristarchus, Herodotus and Vallis Schroteri form an interesting feature group on a diamond-shaped plateau in Oceanus Procellarum (Ocean of Storms). Near the terminator shortly before the full Moon, the feature resembles the face of a cat (or an owl) viewed with south up.
A rayed crater with terraced walls and small central peak, diameter 40 km. Its depth is 3000 m, deep enough to expose the bright anorthosite rock of the lunar crust. Indeed its brightness^ is even detectable in the earthshine portion of a Moon crescent, Event 3. Aristarchus is very young, formed about 500 million years ago. The Aristarchus region is a site of LTP (lunar transient phenomena) glows, probably caused by gases released from decay of radioactive elements. The Apollo-15 and Lunar Prospector flyover also detected the radioactivity of radon gas. The inner walls of Aristarchus are shaded with radial dark bands near the full Moon (T176).
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