Oblique Lunar Orbiter 4 image centered on Riemann with Beals at lower left | |
Coordinates | 39°30′N87°12′E / 39.5°N 87.2°E Coordinates: 39°30′N87°12′E / 39.5°N 87.2°E |
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Diameter | 110 km |
Depth | Unknown |
Colongitude | 274° at sunrise |
Eponym | G. F. Bernhard Riemann |
Riemann (pronounced REE mahn) is a lunar impact crater that is located near the northeastern limb of the Moon, and can just be observed edge-on when libration effects bring it into sight. It lies to the east-northeast of the large walled plain Gauss. To the southeast, beyond sight on the far side, is the crater Vestine.
This is a heavily battered and eroded formation that is only a remnant of its former self. The outer rim has been worn away in many places, and now forms an irregular series of ridges in a rough circle. The rim is overlain along the south-southwestern rim by Beals, and several smaller craters lie along the western and southeast rim. The most intact portion of the outer wall is along the eastern edge.
The interior floor is a mixture of level terrain mixed with rough ground where impacts have stirred up the surface. It is generally less rough in the eastern half, especially near the center. A small, bowl-shaped crater lies on the floor in the southeastern part of the interior, and the faint remnants of several other lesser craters can be observed in the surface.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Riemann.
Riemann | Latitude | Longitude | Diameter |
---|---|---|---|
B | 41.6° N | 85.2° E | 24 km |
J | 37.4° N | 90.2° E | 39 km |
The following craters have been renamed by the IAU.
Anderson is a lunar impact crater that is located on the far side of the Moon. It is located to the northwest of the crater Sharonov, and the satellite crater Sharanov X is attached to the southeast rim of Anderson. To the northeast is the peculiar formation Buys-Ballot, and to the east-southeast lies the larger crater Spencer Jones.
Atwood is a small earth moon impact crater that is located on the Mare Fecunditatis, to the northwest of the prominent crater Langrenus. It forms a triple-crater formation with Naonobu attached to the north rim and Bilharz near the west rim.
Babbage is an ancient lunar impact crater that is located near the northwest limb of the Moon, named after Charles Babbage. It is attached to the southeastern rim of the prominent crater Pythagoras. The crater remnant named South intrudes into the southeastern floor of Babbage.
Beals is a lunar impact crater that is located near the eastern limb of the Moon, and lies across the southwestern rim of the crater Riemann. From the Earth the crater is viewed nearly from on edge, and is best seen during favorable librations. To the west is the large walled plain Gauss.
Calippus is a small lunar impact crater that is located on the eastern edge of the rugged Montes Caucasus mountain range in the northern part of the Moon. It was named after Greek astronomer Callippus of Cyzicus. It lies to the southwest of the crater remnant Alexander, to the northwest of the Mare Serenitatis.
Fontenelle is a lunar impact crater that is located along the northern edge of Mare Frigoris, in the northern part of the Moon. To the northeast is the remnant of the crater Birmingham. Due to its location, this crater appears oval in shape when observed from the Earth because of foreshortening.
Fabry is a large lunar impact crater of the form termed a walled plain. It is located on the far side of the Moon, just beyond the northeastern limb. Parts of this area are sometimes brought into view by the effects of libration, but the terrain is seen from the edge and so not much in the way of detail can be observed.
Porter is a lunar impact crater that is located in the southern part of the Moon, and lies across the northeastern rim of the huge walled plain Clavius. Although generally circular, the form of this crater has been modified by the geometry of the surface on which it was formed. The outer rim is generally lower to the southwest, where it lies on the floor of Clavius. Likewise the interior floor is flatter near this face. In contrast the northeastern floor is rougher and more uneven in the northeastern half.
Birkeland is a lunar impact crater that lies in the southern hemisphere on the far side of the Moon. This crater is attached to the central waist of the oddly shaped Van de Graaff crater formation, and may partly account for that crater's figure-8 shape. To the southeast is the large walled plain Leibnitz.
Bjerknes is a lunar impact crater that is located in the southern hemisphere on the rugged far side of the Moon. The crater lies behind the southeastern limb, and beyond the region that is sometimes brought into sight through libration. Thus this crater can not be viewed from Earth, and has only been seen from orbit. Nearby named craters are Clark to the east, and Pogson to the south-southwest.
C. Mayer is a lunar impact crater that is located at the northern edge of the Mare Frigoris, due north of the prominent crater Aristoteles. Also to the south, but only a third as distant, is the smaller crater Sheepshanks. Due east of C. Mayer is the flooded crater Kane.
Maupertuis is the remnant of a lunar impact crater that is located in the northern part of the Moon's near side. It lies in the stretch of rugged terrain north of Sinus Iridum, a bay in the northwestern corner of Mare Imbrium. To the north lies the crater La Condamine, and Mare Frigoris.
d'Alembert is a large lunar impact crater located in the northern hemisphere on the far side of the Moon, to the northeast of the somewhat smaller walled plain Campbell. Astride the southwest rim of d'Alembert is Slipher. To the north is the crater Yamamoto, and to the south-southwest lies Langevin. This walled plain has the same diameter as Clavius on the near side, making it one of the largest such formations on the Moon.
Debye is a lunar impact crater that is located in the northern hemisphere on the Moon's far side, as seen from the Earth. It lies to the south of the crater Chappell, to the southwest of the walled plain Rowland, and to the east of D'Alembert.
Hédervári is a lunar impact crater that is located in the southern part of the Moon, only a few crater diameters from the south lunar pole. It is attached to the northern rim of the larger crater Amundsen, and lies south of Hale. Due to its location, this crater is viewed nearly from the edge from Earth, which hinders the amount of detail that can be observed. It is also illuminated obliquely by the Sun, and the interior is often cloaked in shadows.
Douglass is a lunar impact crater on the far side of the Moon. It lies to the southwest of the crater Frost and south-southwest of the large walled plain Landau.
Dziewulski is a lunar impact crater on the far side of the Moon. It lies between the craters Edison to the north and Popov to the south. The outer rim of this crater has been considerably worn by impacts, particularly along the southwest quadrant where the satellite crater Dziewulski Q overlies the rim and the interior floor. The northern rim is also heavily disrupted, and several small crater lie along the southeast rim. The interior floor and surrounding terrain has been resurfaced.
Donner is a lunar impact crater on the far side of the Moon. It is located just to the northeast of the Mare Australe, behind the southeastern limb of the Moon. During favorable librations this part of the lunar surface can be brought into view of the Earth, but the site is viewed from the edge and so not much detail can be seen.
Edison is a lunar impact crater on the far side of the Moon. It is located just behind the north-northeastern limb of the Moon, a region that is sometimes brought into sight from Earth during favorable librations. However even at such times not much detail can be discerned, and the crater is better observed by orbiting spacecraft.
Fersman is a large lunar impact crater on the Moon's far side. It lies to the east of the crater Poynting, and west-northwest of Weyl. To the south is the huge walled plain Hertzsprung.