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Necho is a lunar impact crater on the far side of the Moon, and therefore cannot be seen directly from the Earth. It lies to the northeast of the larger crater Langemak, and about a crater diameter to the south-southwest of Bečvář. The most distinctive aspect of this crater is the prominent ray system that surrounds the outer rim. This higher-albedo skirt of ejecta extends in a nearly continuous fashion out for several crater diameters, but is more extensive to the north and northeast than elsewhere. Beyond this continuous skirt, occasional rays and wisps of light material extent outwards for many more crater diameters. Due to its prominent rays and generally very fresh appearance, Necho is mapped as part of the Copernican System.〔The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican System ((online ))〕 The outer rim of Necho is somewhat uneven in form, particularly along the western side where it possesses two inner sides that overlap in almost spiral-like fashion. The rim has a slight outward bulge to the east, and is more uneven along that edge. The inner wall and floor has a high albedo, giving the crater a bright appearance. The inner side is generally wider on the western side, and the interior floor is offset to the eastern half. The crater was informally called "the Bright One" by the Apollo 14 crew.〔(Figure 140 caption ) of ''Apollo Over the Moon: A View From Orbit'', NASA SP-362, 1978〕 It was not formally named until 1976 by the IAU.〔(Necho ), Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)〕 Necho lies at the south edge of an unnamed, highly subdued, 200 km diameter crater which was originally discovered during the Apollo 16 mission and reported by Farouk El-Baz. The name ''Necho'' was proposed for the unnamed crater, but the name was eventually adopted for this smaller crater.〔Apollo 16 Preliminary Science Report (NASA SP-315), 1972, Chapter 29, Part H: ''Discovery of Two Lunar Features'' ()〕 == 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 Necho. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Necho (crater)」の詳細全文を読む スポンサード リンク
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