Helmert (crater)

Helmert

Apollo 8 Hasselblad camera image
Diameter	26 km
Depth	Unknown
Colongitude	273° at sunrise
Eponym	Friedrich R. Helmert

Helmert is a lunar crater at the southern edge of the Mare Smythii. It lies near the eastern limb of the Moon, and from the Earth it is seen nearly from the side. The visibility of this feature can be strongly affected by libration of the Moon in its orbit.

This crater forms part of a merged pair with the similar crater Kao on its northern side. There is a gap in the rims where these two craters are joined, and the interior floors have been resurfaced by lava, leaving a level surface across the bottom of both craters. This floor is nearly featureless, and has the same low albedo as the dark lunar mare to the north. The outer rim has a small crater joined to the eastern edge of the northern gap, but is otherwise not overlain by any notable craters.

The crater's name was approved by the IAU in 1973.

References

• Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097. {{cite book}}: Invalid |ref=harv (help)
• Blue, Jennifer (July 25, 2007). "Gazetteer of Planetary Nomenclature". USGS. Retrieved 2007-08-05. {{cite web}}: Invalid |ref=harv (help)
• Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4. {{cite book}}: Invalid |ref=harv (help)
• 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. {{cite book}}: Invalid |ref=harv (help)
• McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report. Retrieved 2007-10-24. {{cite web}}: Invalid |ref=harv (help)
• 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. {{cite journal}}: Invalid |ref=harv (help)
• Moore, Patrick (2001). On the Moon. Sterling Publishing Co. ISBN 978-0-304-35469-6. {{cite book}}: Invalid |ref=harv (help)
• Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3. {{cite book}}: Invalid |ref=harv (help)
• Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4. {{cite book}}: Invalid |ref=harv (help)
• Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. ISBN 978-0-486-20917-3. {{cite book}}: Invalid |ref=harv (help)
• Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6. {{cite book}}: Invalid |ref=harv (help)
• Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1. {{cite book}}: Invalid |ref=harv (help)