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Lat: 35.8°S, Long: 4.2°W, Diam: 62 km, Depth: 1.59 km, Rükl: 65, Eratosthenian

external image normal_lexell_040807_04h34tu.jpg
François Emond North is at about 2 o'clock in this view which includes 23-km Lexell B at the center of the lower margin. Several other lettered craters associated with Lexell, Sasserides and Orontius are also visible.


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Description: Elger

(IAU Directions) LEXELL.--On the W. of Walther extends an immense plain of irregular outline, which is at least equal to it in area. Though no large formation is found thereon; many ridges, short crater-rows, and ordinary craters figure on its rugged superficies; and on its borders stand some very noteworthy objects, among them, on the S., the walled-plain Lexell, about 32 miles in diameter, which presents many points of interest. Its irregular wall, rising, at one point on the S.E., to a height of nearly 8,000 feet, is on the N.E. almost completely wanting, only very faint indications of its site being traceable, even under a low morning sun. On the opposite side it is boldly terraced, and has a large crater on its summit. The interior, the tone of which is conspicuously darker than that of the region outside, contains a small central hill, with two craters connected with it. The low N.E. margin is traversed by a delicate valley, which, originating on the N. side of the great plain, crosses the E. quarter of Lexell and terminates apparently on the S.E. side of the floor.

Description: Wikipedia


Additional Information

Depth data from Kurt Fisher database
  • Westfall, 2000: 1.59 km


  • Anders Johan Lexell (December 24, 1740 - December 11, 1784) was a Finland-Swedish-born Russian astronomer and mathematician. He studied the motions of comets. He computed the orbit of comet "D/1770 L1" (Lexell), and it is named after him although it was discovered by Charles Messier. This comet made the closest known approach to Earth by any comet in history (although asteroids have come closer), making it the first known near-Earth object; the exact distance is not known but has been estimated to have been within 3 million km. Lexell showed that the comet had had a much larger perihelion distance until an encounter with Jupiter in 1767, and he predicted that, after encountering Jupiter again at an even closer distance two revolutions later, in 1779, it would be altogether expelled from the inner solar system. He was also the first to compute the orbit of Uranus soon after its discovery and realized from its orbit that it was a planet rather than a comet. He also found that Uranus was being perturbed and deduced the existence of another planet (the eventual Neptune), although the position of Neptune was not calculated until much later by Urbain Le Verrier.
  • According to Whitaker (p. 218), this name was introduced by Schröter.

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