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Wilkins (crater)
Wilkins is a lunar impact crater that lies in the rugged highlands in the southeastern part of the Moon's near side. It is located to the southwest of the crater Pons and the long Rupes Altai scarp. Just to the southeast lies the larger crater Zagut, and to the north-northwest is the still-larger Sacrobosco. Wilkins is 57 kilometers in diameter. The outer rim of Wilkins has received considerable damage, leaving sections nearly disintegrated. The most intact portion is in the south, although even this rim is worn and has a valley to the southwest. There is a narrow curving gap in the western rim, with the northern edge formed by a pair of small, joined craters that include Wilkins A. The rim to the northeast barely survives, and the rim here is low and scarred by valleys and old craters. The interior floor of Wilkins is relatively flat and featureless, except for a ghost-crater rim along the southwest edge. The ray material from Tycho lies north of the crater rim. The crater i ... [...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] |
Hugh Percy Wilkins
Hugh Percy Wilkins (4 December 1896 –23 January 1960) was a Welsh-born engineer and amateur astronomer. He was born Hugh Percival Wilkins in Carmarthen, where he received his early education, then lived near Llanelli prior to moving to England. During the First World War he served in the Royal Army Corps. By profession, he was a mechanical engineer and civil servant, but his reputation rests on his achievements as an amateur astronomer, particularly as a selenographer. He was initially elected to the British Astronomical Association (BAA) on 27 February 1918 at the invitation of W F Denning and Fiammetta Wilson. At some point his membership lapsed and he rejoined on 25 March 1936 this time at the invitation of Robert Barker and Walter Goodacre. Wilkins was elected to the fellowship of the Royal Astronomical Society on 11 May 1945. He was Director of the BAA's Lunar Section from 1946 to 1956. He produced a 100" map of the Moon, which included new names for a number of ... [...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] |
Pons (crater)
Pons is a lunar impact crater that is located to the west of the prominent Rupes Altai scarp. It was named after French astronomer Jean-Louis Pons. It lies to the southeast of the crater Sacrobosco, and southwest of Polybius. To the northwest along the same flank of the formation is the crater Fermat Pierre de Fermat (; between 31 October and 6 December 1607 – 12 January 1665) was a French mathematician who is given credit for early developments that led to infinitesimal calculus, including his technique of adequality. In particular, he i .... The rim of Pons is somewhat elongated in shape, being longer along a northeast–southwest axis than in the perpendicular direction. The outer wall is irregular and notched, particularly at the northeastern end where it is partly overlain by the satellite crater Pons D and multiple smaller formations. The interior is uneven, with low ridges projecting from the north and southeastern rims. Satellite craters By convention these featur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rupes Altai
Rupes Altai is an escarpment in the lunar surface that is located in the southeastern quadrant of the Moon's near side. It is named for the Altai Mountains in Asia, and is the most prominent lunar escarpment. The selenographic coordinates of this feature are , and it has a length of about 427 km. The southeastern end of the cliff terminates along the western edge of the crater Piccolomini. It then arcs irregularly towards the north, climbing to heights of nearly a kilometer. The northern end of the arc is an irregular region with no clearly defined terminus, where it brackets the prominent craters Theophilus, Cyrillus, and Catharina. This cliff forms the southwestern rim of the Nectaris impact basin. This feature is difficult to locate during the full moon when the sunlight is nearly overhead. It appears as a bright, winding line about five days after the new moon, and casts a long, irregular shadow about four days after the full moon, when the sunset terminator is nearby and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escarpment
An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escarpment''. Some sources differentiate the two terms, with ''escarpment'' referring to the margin between two landforms, and ''scarp'' referring to a cliff or a steep slope. In this usage an escarpment is a ridge which has a gentle slope on one side and a steep scarp on the other side. More loosely, the term ''scarp'' also describes a zone between a coastal lowland and a continental plateau which shows a marked, abrupt change in elevation caused by coastal erosion at the base of the plateau. Formation and description Scarps are generally formed by one of two processes: either by differential erosion of sedimentary rocks, or by movement of the Earth's crust at a geologic fault. The first process is the more common type: the escarpment is a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zagut (crater)
Zagut is a crater located in the heavily impacted southeast sector of the Moon. It is almost surrounded by other named craters, with Wilkins to the northwest, Lindenau to the east, Rabbi Levi in the southeast, and Celsius to the southwest. It is named after Jewish Spanish astronomer and rabbi Abraham Zacuto Abraham Zacuto ( he, , translit=Avraham ben Shmuel Zacut, pt, Abraão ben Samuel Zacuto; 12 August 1452 – ) was a Castilian astronomer, astrologer, mathematician, rabbi and historian who served as Royal Astronomer to King John II of Portugal. .... The rim of Zagut is worn and irregular, especially to the north and east. The east rim is overlain by Zagut E, a crater with an irregular and flat floor. The floor of Zagut itself is also relatively flat, and the center is occupied by the crater Zagut A instead of a peak. 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 Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrobosco (crater)
Sacrobosco is an irregular lunar impact crater that is located in the rugged southern highlands to the west of the Rupes Altai escarpment. It is a readily identified feature due to the three circular craters that lie on its floor. The rim of Sacrobosco is heavily worn and eroded, especially in the northeast. The floor is relatively flat in the south, except where overlain by Sacrobosco A and B, but is somewhat irregular in the northeast. To the northwest of Sacrobosco is the double crater Abenezra and Azophi. To the east-northeast is Fermat, and to the south-southwest lies Pontanus. 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 Sacrobosco. References * * * * * * * * * * * * {{refend Impact craters on the Moon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palimpsest
In textual studies, a palimpsest () is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off so that the page can be reused for another document. Parchment was made of lamb, calf, or kid skin and was expensive and not readily available, so, in the interest of economy, a page was often re-used by scraping off the previous writing. In colloquial usage, the term ''palimpsest'' is also used in architecture, archaeology and geomorphology to denote an object made or worked upon for one purpose and later reused for another; for example, a monumental brass the reverse blank side of which has been re-engraved. Etymology The word ''palimpsest'' derives from the Latin '' palimpsestus'', which derives from the Ancient Greek παλίμψηστος (, from + = 'again' + 'scrape'), a compound word that describes the process: "The original writing was scraped and washed off, the surface resmoothed, and the new literary material written o ... [...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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