is a
Lunar Impact Crater that is located to the southeast of
Cassini Crater near the eastern edge of
Mare Imbrium . It lies just to the west of the
Montes Caucasus range, which forms the eastern shore of the
Mare . To the southwest is the prominent
Aristillus Crater .
The rim of Theaetetus is distinctly
Polygon al in shape, with a slight rounding at the vertices. There is a low outer
Rampart and a slight central rise on the crater floor, which is offset to the northeast of the crater mid-point. The interior is otherwise relatively featureless.
This crater has been noted in the past as a site of possible
Transient Lunar Phenomena . In
1902 , a white cloud was observed to briefly form in the vicinity of the crater. Other observers, including
Patrick Moore and
W. H. Pickering , have also noted unusual appearances in this area.
