Langrenus is an

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

located near the eastern

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 ...

limb. The feature is circular in shape, but appears oblong due to foreshortening. It lies on the eastern shore of the

Mare Fecunditatis Mare Fecunditatis (Latin ''fēcunditātis'', the "Sea of Fecundity" or "Sea of Fertility") is a lunar mare in the eastern half of the visible Moon. The mare has a maximum diameter of 840 km. __NOTOC__ Description The Fecunditatis basin form ...

. To the south is the overlapping crater pair Vendelinus and the smaller Lamé. The inner wall of Langrenus is wide and irregularly terraced, with an average width of about 20 kilometers. The outer ramparts are irregular and hilly, and there is a bright, fragmented

ray system A ray system comprises radial streaks of fine ''ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter ...

spread across the mare to the west. The interior of the crater has a higher

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refle ...

than the surroundings, so the crater appears bright when the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

is overhead. The crater floor is covered by many

boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In ...

s, and is slightly irregular in the northwest half. The central peaks rise about a kilometer above the floor, and a peak on the eastern rim ascends to an altitude of 3 km. On December 30, 1992, Audouin Dollfus of the

Observatoire de Paris The Paris Observatory (french: Observatoire de Paris ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its histo ...

observed a series of glows on the floor of this crater using the one-meter

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to obse ...

. These glows changed form with time, and Dollfus expressed the belief that this was likely a gaseous emission. The cracked floor of the crater may have been the source of the gas. Flemish astronomer Michel Florent van Langren was the first person to draw a lunar map while giving names to many of the features, in 1645. He named this crater after himself; it is the only one of his named features that has retained his original designation. Mare Fecunditatis

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 Langrenus. Many of the more significant associated craters that surround Langrenus have since been renamed by the IAU. * Langrenus A — ''See'' Barkla. * Langrenus B — ''See'' Naonobu. * Langrenus C — ''See'' Acosta. * Langrenus D — ''See'' Al-Marrakushi. * Langrenus F — ''See'' Bilharz. * Langrenus J — ''See'' Somerville. * Langrenus K — ''See'' Atwood. File:Langrenus M crater AS15-M-2388.jpg, Langrenus M File:Langrenus M crater AS16-P-4410.jpg, Langrenus M File:Langrenus X crater AS15-M-2388.jpg, Langrenus X (lower left) and unnamed crater (upper right)

References

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External links

LAC-80

AS16-M-0666
view from

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth human spaceflight, crewed mission in the United States Apollo program, Apollo space program, administered by NASA, and the fifth and penultimate to Moon landing, land on the Moon. It was the second o ...

At the Top of the Avalanche
on the central peak of Langrenus, from

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* {{cite web , last = Wood , first = Chuck , date = November 25, 2007 , title = Moving Eastward , publisher = Lunar Photo of the Day , url = http://www2.lpod.org/wiki/November_25,_2007 , access-date = 2015-11-08
Lights glow on Moon
Impact craters on the Moon