Coordinates | 18°44′N107°48′W / 18.74°N 107.80°W |
---|---|
Diameter | 64.73 km (40.22 mi) |
Depth | Unknown |
Colongitude | 108° at sunrise |
Eponym | Dinsmore Alter |
Alter is a lunar impact crater that is located in the northern hemisphere on the far side of the Moon. It lies to the southwest of the larger crater Robertson, and to the east of Ohm.
The outer rim of Alter has been degraded by subsequent erosion, most notably at the northern and southern extremes. There is a small crater lying across the south-southeast rim. A cleft runs across the floor from the southern rim toward the north-northeast. Ray material cross the crater floor from the east, forming a pair of faint bands.
Prior to formal naming by the IAU in 1970, [1] Alter was called Crater 257. [2] The crater Alter W, to the northwest of Alter, was called Crater 255. A crater that is currently unnamed, between Alter W and Comrie K, was called Crater 254.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Alter.
Alter | Latitude | Longitude | Diameter |
---|---|---|---|
K | 16.3° N | 106.0° W | 22 km |
W | 20.4° N | 109.2° W | 52 km |
Landau is a large lunar impact crater that is located in the northern hemisphere on the far side of the Moon. It was named after physicist Lev Landau. The crater Wegener is attached to the northeastern rim. Attached to the southeastern rim is Frost.
Avicenna is a lunar impact crater that lies on the far side of the Moon, just beyond the western limb on the northern rim of the Lorentz basin. It is named after the Persian polymath Avicenna. It lies to the north-northwest of the larger crater Nernst, and to the southeast of Bragg.
Robertson is an important lunar impact crater that is located on the far side of the Moon, just beyond the western limb. It lies just to the south of Berkner, a formation with a comparable size but more eroded features. Just to the east is Helberg, and to the southwest is Alter.
Fechner is a lunar impact crater that lies on the far side of the Moon's southern hemisphere, attached to the western rim of the large walled plain Planck. The eastern rim of Fechner intersects the Vallis Planck, a long, wide cleft in the surface that follows a course to the north-northwest. This valley intrudes into the southeastern rim of the crater, then continues northwards from the periphery of the northeast rim.
Becquerel is a lunar impact crater that lies in the northern hemisphere on the far side of the Moon. This is an ancient and heavily worn formation that is now little more than an irregular buri in the surface. The outer rim has been worn and reshaped until it forms a rugged, mountainous region around the flatter interior.
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.
Bell is a lunar impact crater that is located on the far side of the Moon, just past the western limb. It lies in an area of terrain that is marked by many small craters, a number of which are satellite craters of Bell listed in the table below. Bell lies within two crater diameters of Laue to the north, and to the west of the smaller Helberg.
Bunsen is a lunar impact crater that lies near the northwestern limb of the Moon. It is located to the west of the Oceanus Procellarum and the crater von Braun. To the southeast is the crater Lavoisier, and to the northeast lies Gerard. Northwest of Bunsen, on the far side of the Moon, is McLaughlin. Due to its position this crater appears foreshortened when viewed from the Earth, and its visibility is affected by libration.
Blanchard is a lunar impact crater that lies on the far side of the Moon, just behind the southwestern limb. It lies to the south-southwest of the crater Arrhenius, and northwest of Pilâtre. Further to the south is the rugged terrain to the north of the walled plain Hausen.
Davisson is a lunar impact crater that is located on the far side of the Moon from the Earth. This crater lies across the eastern rim of the huge walled plain Leibnitz, and the rim and outer rampart intrudes into the interior floor of Leibnitz. To the east-northeast of Davisson is the walled plain Oppenheimer, a formation only somewhat smaller than Leibnitz.
Chapman is a lunar impact crater that lies just beyond the northwest rim of the Moon, on the far side as seen from the Earth. It lies to the northeast of the crater Rynin, and southward of the large walled plain Poczobutt.
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.
Danjon is a lunar impact crater on the far side of the Moon. It lies less than a crater diameter to the east-southeast of the larger crater Langemak. To the east-northeast of Danjon is the crater Perepelkin, and due south lies the walled plain Fermi.
Dellinger is a lunar impact crater that is located on the Moon's far side. It is attached to the southern rim of the crater Pannekoek. To the southeast lies the crater Marconi, and to the southwest is Chauvenet.
Frost is a lunar impact crater that is attached to the southern rim of the walled plain Landau, and lies on the far side of the Moon. Just to the east is Petropavlovskiy, and to the northeast along the edge of Landau is Razumov. The crater Douglass is located less than a crater diameter to the west-southwest.
Fridman is the remains of a lunar impact crater on the far side of the Moon. It lies due south of the huge walled plain Hertzsprung, and is attached to the northeastern rim of the crater Ioffe.
Richardson is a large lunar impact crater located on the Moon's far side, just behind the eastern limb. It lies to the south of the huge walled plain Harkhebi, and to the east-southeast of the crater Vestine. Just to the northeast is Szilard, and to the southeast is Artamonov.
Wegener is a lunar impact crater that is located in the Moon's northern hemisphere, about midway between the equator and the north pole. It lies on the far side from the Earth, behind the northwestern limb. The southwestern rim of Wegener intrudes slightly into the much larger walled plain Landau. Attached to the eastern rim is the crater Stefan.
Wood is a lunar impact crater that lies entirely within the interior of the much larger walled plain Landau, on the far side of Moon. Wood is situated along the northwestern part of the floor of Landau, and shares a common northwestern rim with the larger impact. The inner wall of the northwest rim extends inward about halfway toward the crater midpoint, where there is a central peak. The rim of Wood is somewhat worn and uneven, with a small crater laid across the southwest section. The surviving interior floor is nearly level and is marked only by a few small craters.
Parenago is an impact crater on the Moon's far side, behind the eastern limb. Nearly attached to the east-southeastern outer rim of Parengo is the crater Berkner. To the south-southwest lies Comrie.