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Theaetetus is a lunar impact crater that is located to the southeast of the crater Cassini near the eastern edge of Mare Imbrium. It was named after the ancient Greek mathematician Theaetetus.[1] 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 crater Aristillus.

Theaetetus - LROC - WAC.JPG
LRO image
Coordinates37°00′N 6°00′E / 37.0°N 6.0°E / 37.0; 6.0Coordinates: 37°00′N 6°00′E / 37.0°N 6.0°E / 37.0; 6.0
Diameter25 km
Depth2.8 km
Colongitude354° at sunrise

The rim of Theaetetus is distinctly polygonal 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 midpoint. The interior is otherwise relatively featureless.

Theaetetus crater taken from Earth in 2012 at the University of Hertfordshire's Bayfordbury Observatory with the telescopes Meade LX200 14" and Lumenera Skynyx 2-1
Oblique view from Apollo 15

This crater has been noted in the past as a site of possible transient lunar phenomena. In 1902, a white cloud was observed briefly in the vicinity of the crater. Other observers, including Patrick Moore and W. H. Pickering, have also noted unusual appearances in this area.


  1. ^ "Theaetetus (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  • Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.
  • Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4.
  • Cocks, Elijah E.; Cocks, Josiah C. (1995). Who's Who on the Moon: A Biographical Dictionary of Lunar Nomenclature. Tudor Publishers. ISBN 978-0-936389-27-1.
  • McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report. Retrieved 2007-10-24.
  • Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186. Bibcode:1971SSRv...12..136M. doi:10.1007/BF00171763.
  • Moore, Patrick (2001). On the Moon. Sterling Publishing Co. ISBN 978-0-304-35469-6.
  • Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3.
  • Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4.
  • Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. ISBN 978-0-486-20917-3.
  • Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6.
  • Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.