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Hommel (crater)
Hommel is a lunar impact crater located in the southeast section of the Moon, in a region that is deeply impacted with a multitude of impact craters. The most notable craters nearby are Pitiscus to the north; Rosenberger due east; and Nearch to the southeast. The prominent crater Vlacq is nearly attached to the northeast rim. Also nearby is Asclepi to the west. Hommel is about 120 kilometers in diameter and its walls reach heights of 2,800 meters. It is from the Pre-Nectarian period, 4.55 to 3.92 billion years ago.''Autostar Suite Astronomer Edition''. CD-ROM. Meade, April 2006. The eroded outer wall of Hommel is overlain and incised by a number of smaller but still sizeable craters. Hommel C overlays the western rim and Hommel A the north. Intruding into the rim are Hommel H to the northwest, Hommel B in the east, and Hommel P along the southern wall. These craters are in turn overlain by smaller craterlets. The crater Hommel D lies on the southern part of the inner floor, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Orbiter 4
Lunar Orbiter 4 was a robotic U.S. spacecraft, part of the Lunar Orbiter program, Lunar Orbiter Program, designed to orbit the Moon, after the three previous orbiters had completed the required needs for Project Apollo, Apollo mapping and site selection. It was given a more general objective, to "perform a broad systematic photographic survey of lunar surface features in order to increase the scientific knowledge of their nature, origin, and processes, and to serve as a basis for selecting sites for more detailed scientific study by subsequent orbital and landing missions". It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data. Mission Summary The spacecraft was placed in a Free-return trajectory, cislunar trajectory and injected into an elliptical near polar high lunar orbit for data acquisition. The orbit was with an inclination of 85.5 degrees and a period of 12 hours. After initial photography on May 11, 1967 problems started occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Hommel
Johann Hommel (also ''Johannes Homelius'', ''Hummelius'', ''Homilius'', ''Hummel''; 2 February 1518, Memmingen – 4 July 1562, Leipzig) was a German astronomer and mathematician. Work Hommel was appointed professor of mathematics at the University of Leipzig in 1551. In 1552 or 1553, Richard Cantzlar introduced transversal dot lines in graduations. It was a variant of the zigzag line system introduced by Hommel. Tycho Brahe obtained the zigzag line system from Hommel. The lunar crater Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, all of which were formed by impacts. The International Astronomical Union currently recognizes 9,137 craters, of which 1,675 have been dated. History The wor ... Hommel is named after him. Sources * Johann Daniel Schulze, ''Abriß einer Geschichte der Leipziger Universität'', Hinrichs, 1810, p. 48. * Kevin Krisciunas (1999)"Observatories" External links * 16th-century German astronomers 16th- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Craters
Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, all of which were formed by impacts. The International Astronomical Union currently recognizes 9,137 craters, of which 1,675 have been dated. History The word ''crater'' was adopted from the Greek word for "vessel" (, a Greek vessel used to mix wine and water). Galileo built his first telescope in late 1609, and turned it to the Moon for the first time on November 30, 1609. He discovered that, contrary to general opinion at that time, the Moon was not a perfect sphere, but had both mountains and cup-like depressions. These were named craters by Johann Hieronymus Schröter (1791), extending its previous use with volcanoes. Robert Hooke in ''Micrographia'' (1665) proposed two hypotheses for lunar crater formation: one, that the craters were caused by projectile bombardment from space, the other, that they were the products of subterranean lunar volcanism. Scientific opinion as to the origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Lunar impact craters range from microscopic craters on lunar rocks returned by the Apollo Program and small, simple, bowl-shaped depressions in the lunar regolith to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Europa, Io and Titan, visible impact craters are less common because they become eroded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia). The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at , with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density. The Moon orbits Earth at an average distance of , or about 30 times Earth's diameter. Its gravitational influence is the main driver of Earth's tides and very slowly lengthens Earth's day. The Moon's orbit around Earth has a sidereal period of 27.3 days. During each synodic period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitiscus (crater)
Pitiscus is a lunar impact crater that lies in the southern part of the Moon's near side, just to the northwest of the larger crater Hommel. It was named after German mathematician Bartholomaeus Pitiscus in 1935. The crater is worn, but still forms a prominent feature upon the surface. The rim is roughly circular, but appears oval from the Earth due to foreshortening. There is an outward bulge to the south-southeast where the interior has slumped. The remainder of the inner wall still displays terraces, although they are worn and rounded due to erosion. The interior floor is level and appears to have been resurfaced by lava. There is a low central peak formation at the midpoint of the interior, and the northern end of this ridge is overlaid by the circular crater Pitiscus A. A slumped and somewhat irregular crater, Pitiscus E, lies along the inner wall to the west-southwest. The interior floor is also marked by several other tiny craters alongside the eastern interior wall. Piti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosenberger (crater)
Rosenberger is an old lunar impact crater in the southeastern part of the Moon. It was named after German astronomer Otto August Rosenberger. This crater is located in a region rich with prominent craters. The slightly smaller Vlacq is nearly attached to the northwestern outer rim of Rosenberger. Other nearby craters of note include Biela Biela may refer to: * Biela, Bohemia, former name of a town in eastern Bohemia, now Luže *Biela, Greater Poland Voivodeship (west-central Poland) *Biela (river), a river in eastern Germany. *Wilhelm Freiherr von Biela, an Austrian military office ... to the east, Hagecius to the south-southeast, and Nearch to the south-southwest. Due west past Vlacq is Hommel. This crater has been heavily eroded by a history of impacts, so that the outer rim has become rounded and somewhat indistinct. As a result, the crater possesses only a shallow rise along the rim edge, and it nearly forms a circular depression in the surface. The satellite crater Ros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nearch (crater)
Nearch is a lunar impact crater that is located in the southeastern part of the Moon, to the southeast of the crater Hommel. North of Nearch is Vlacq, and to the northeast lies Rosenberger. The crater is 76 kilometers in diameter and 2.9 kilometers deep. It is from the Pre-Nectarian period, 4.55 to 3.92 billion years ago.''Autostar Suite Astronomer Edition''. CD-ROM. Meade, April 2006. The outer rim of Nearch has been worn by smaller impacts, and is overlain by a few more significant craters along the eastern rim. The most notable of these is Nearch A, a 43-kilometer-diameter crater that intrudes into the southeastern rim of Nearch. Small craters have also disrupted the rim to the north and west. The remainder of the rim is relatively intact, and retains its generally circular form. The inner walls of the crater slope down to a relatively level interior floor. This bottom floor is nearly featureless except for a few tiny craterlets scattered across the surface. In the southea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vlacq (crater)
Vlacq is a prominent lunar impact crater that is located in the southeastern part of the Moon, and appears foreshortened when viewed from the Earth. This crater is adjacent to the northeastern rim of the larger Hommel, and to the northwest rim of Rosenberger. This crater has become eroded, but not to the degree of the larger neighboring craters. The satellite crater Vlacq G intrudes into the southern rim of Vlacq, and is overlaid in turn along the southwest rim by the sharp-rimmed Vlacq B. The satellite crater Vlacq C is attached to the northeastern exterior rim of Vlacq. The interior floor of Vlacq has been resurfaced by lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ..., leaving a nearly level base. The southwest half of the floor, however, is overlaid by ejecta from nearb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asclepi (crater)
Asclepi is a heavily eroded lunar impact crater that lies in the rugged southern highlands of the Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of .... The outer rim has been worn down and rounded by many millions of years of subsequent impacts, so that it is now nearly level with the surrounding terrain. As a result, the crater is now little more than a depression in the surface. The interior is nearly flat and relatively featureless. The rim of Asclepi is marked only by a small crater across the western rim, and several tiny craterlets. The satellite crater Hommel K is a more recent impact that is attached to the southeast rim. This is a bowl-shaped formation with a sharp edge and a small central floor. Nearby craters of note include Pitiscus to the north-northeast, Hommel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pre-Nectarian
The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago (the time of the initial formation of the Moon) to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Nectarian period. Description Pre-Nectarian rocks are rare in the lunar sample suite; they are mostly composed of lunar highlands material which have been heavily churned, brecciated, and thermally affected by subsequent impacts, particularly during the Heavy Bombardment Eon (HBE; a period of 0.6-1 Gy from the formation of the Moon until at least the formation of the Imbrium Basin ~3.9 Ga, or even later with the formation of Orientalis Basin) that marks the approximate beginning of the Nectarian period. The primary pre-Nectarian lunar highland material is dominated by the rock type anorthosite, which suggests that the early stage of lunar crustal formation occurred via mineral crystallization of a global magma ocean. This geologic period has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalmbach Books
Kalmbach Media (formerly Kalmbach Publishing Co.) is an American publisher of books and magazines, many of them railroad-related, located in Waukesha, Wisconsin. History The company's first publication was ''The Model Railroader'', which began publication in the summer of 1933 with a cover date of January 1934. A press release announcing the magazine appeared in August 1933, but did not receive much interest. In 1940, business was good enough for Kalmbach to launch another magazine about railroads in general with the simple title of ''Trains Magazine''. From its first issue dated November 1940, it grew quickly from an initial circulation of just over 5,000. Kalmbach became exclusively a publisher when it discontinued its printing operations in 1973, opting to contract production from other printers. In 1985, Kalmbach purchased AstroMedia Corporation, adding its four magazines: ''Astronomy'', ''Deep Sky'', the children's science magazine ''Odyssey'' and ''Telescope Making'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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