Longomontanus is an ancient

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

impact crater An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...

located in the rugged southern highlands to the southwest of the bright ray crater

Tycho Tycho is a masculine given name, a latinization of Greek Τύχων, from the name of Tyche (), the Greek goddess of fortune or luck. The Russian form of the name is '' Tikhon'' (Тихон). People Given name * Tycho Brahe (1546–1601), Dan ...

. Longomontanus is of the variety of large lunar formations called a "walled plain", although it is actually more of a circular depression in the surface. Because of its location, Longomontanus appears distinctly

oval An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas of mathematics (projective geometry, technical drawing, etc.), it is given a more precise definition, which may inc ...

in shape due to foreshortening. To the southeast of Longomontanus is the even larger formation

Clavius Christopher Clavius, (25 March 1538 – 6 February 1612) was a Jesuit German mathematician, head of mathematicians at the , and astronomer who was a member of the Vatican commission that accepted the proposed calendar invented by Aloysius ...

, and to the east is

Maginus Giovanni Antonio Magini (in Latin, Maginus) (13 June 1555 – 11 February 1617) was an Italian astronomer, astrologer, cartographer, and mathematician. His Life He was born in Padua, and completed studies in philosophy in Bologna in 1579. His ...

. North of the rim is the irregular crater Montanari, which in turn is joined at its northern rim by

Wilhelm Wilhelm may refer to: People and fictional characters * William Charles John Pitcher, costume designer known professionally as "Wilhelm" * Wilhelm (name), a list of people and fictional characters with the given name or surname Other uses * Wilhe ...

. The wall of Longomontanus is heavily worn and incised by past impacts, and the rim is essentially level with the surrounding

terrain Terrain (), alternatively relief or topographical relief, is the dimension and shape of a given surface of land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientati ...

. The northern rim especially is impacted with multiple overlapping craterlets. To the east of the rim is a semi-circular ridge that has the appearance of an overlapped crater rim. The crater floor of Longomontanus is relatively flat, with a low cluster of central peaks somewhat offset to the west. Longomontanus is one of the largest craters of

Nectarian The Nectarian Period of the lunar geologic timescale was from 3.920 billion years ago to 3.850 billion years ago. It is the period during which the Nectaris Basin and other major basins were formed by large impact events. Ejecta from Nectaris for ...

age.The geologic history of the Moon

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

Professional Paper 1348. By Don E. Wilhelms, John F. McCauley, and Newell J. Trask. U.S. Government Printing Office, Washington: 1987. Table 9-4.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Longomontanus.

References

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External links

* {{cite web , last = Wood , first = Chuck , date = December 30, 2007 , url = http://www.lpod.org/?m=20071230 , title = Splattered , publisher = Lunar Photo of the Day , access-date = 2008-01-02 , url-status = dead , archive-url = https://web.archive.org/web/20071231060800/http://www.lpod.org/?m=20071230 , archive-date = December 31, 2007 Impact craters on the Moon