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Snellius (crater)
Snellius is a Lunar craters, lunar impact crater located near the southeast limb of the Moon. The rim of Snellius is heavily worn and eroded, with overlapping craterlets. The floor is somewhat irregular and uneven. The western rim marks the start of the Vallis Snellius, one of the longest valleys on the Moon. It continues nearly 500 kilometers to the northwest to near the edge of Mare Nectaris. Its origin is most likely associated with the formation of the lunar mare. To the northeast is the large crater Petavius (crater), Petavius. South of Snellius is the crater Stevinus (crater), Stevinus. Just to the northwest is Snellius A, a crater with a notable ray system that overlaps the southwest reaches of Mare Fecunditatis to the north. It is named after Dutch astronomer, mathematician and physicist, Willebrord Snellius. 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 Snelli ...
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Ray System
In planetary geology, a ray system comprises radial streaks of fine '' ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter of their originating crater, and are often accompanied by small secondary craters formed by larger chunks of ejecta. Ray systems have been identified on the Moon, Earth ( Kamil Crater), Mercury, and some moons of the outer planets. Originally it was thought that they existed only on planets or moons lacking an atmosphere, but more recently they have been identified on Mars in infrared images taken from orbit by '' 2001 Mars Odyssey''s thermal imager. Rays appear at visible, and in some cases infrared wavelengths, when ejecta are made of material with different reflectivity (i.e., albedo) or thermal properties from the surface on which they are deposited. Typically, visible rays have a higher albedo than th ...
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Sterling Publishing Co
Sterling Publishing Company, Inc. is a publisher of a broad range of subject areas, with multiple imprints and more than 5,000 titles in print. Founded in 1949 by David A. Boehm, Sterling also publishes books for a number of brands, including AARP, Hasbro, Hearst Magazines, and '' USA TODAY'', as well as serves as the North American distributor for domestic and international publishers including: Anova, the Brooklyn Botanic Garden, Carlton Books, Duncan Baird, Guild of Master Craftsmen, the Orion Publishing Group, and Sixth & Spring Books. Sterling Publishing became a wholly owned subsidiary of Barnes & Noble, when the book retailer acquired it in 2003. On January 5, 2012, ''The Wall Street Journal'' reported that Barnes & Noble had put its Sterling Publishing business up for sale. Negotiations failed to produce a buyer, however, and as of March 2012 Sterling was reportedly no longer for sale. In January 2022, Sterling rebranded as Union Square & Co. In March 2022, the c ...
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Jonathan's Space Report
''Jonathan's Space Report'' (JSR) is a newsletter about the Space Age hosted at Jonathan's Space Page. It is written by Jonathan McDowell, a Center for Astrophysics Harvard & Smithsonian astrophysicist. It is updated as McDowell's schedule permits, but he tries to publish two issues each month. Originally, the website was hosted on a Harvard University account, but it was moved in late 2003 to a dedicated domain. Started in 1989, the newsletter reports on recent space launches, International Space Station activities, spacecraft developments, and newly released space-related data. McDowell's report occasionally corrects NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...'s official web sites, or provides additional data on classified launches that are not available elsewhere ...
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Cambridge University Press
Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessment to form Cambridge University Press and Assessment under Queen Elizabeth II's approval in August 2021. With a global sales presence, publishing hubs, and offices in more than 40 countries, it published over 50,000 titles by authors from over 100 countries. Its publications include more than 420 academic journals, monographs, reference works, school and university textbooks, and English language teaching and learning publications. It also published Bibles, runs a bookshop in Cambridge, sells through Amazon, and has a conference venues business in Cambridge at the Pitt Building and the Sir Geoffrey Cass Sports and Social Centre. It also served as the King's Printer. Cambridge University Press, as part of the University of Cambridge, was a ...
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United States Geological Survey
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March 3, 1879, to study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The agency also makes maps of planets and moons, based on data from U.S. space probes. The sole scientific agency of the U.S. Department of the Interior, USGS is a fact-finding research organization with no regulatory responsibility. It is headquartered in Reston, Virginia, with major offices near Lakewood, Colorado; at the Denver Federal Center; and in NASA Research Park in California. In 2009, it employed about 8,670 people. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on its hundredth anniversary, was "Earth Science in the Pub ...
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NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ...
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Willebrord Snellius
Willebrord Snellius (born Willebrord Snel van Royen) (13 June 158030 October 1626) was a Dutch astronomer and mathematician, commonly known as Snell. His name is usually associated with the law of refraction of light known as Snell's law. The lunar crater Snellius (crater), Snellius is named after Willebrord Snellius. The Royal Netherlands Navy has named three survey ships after Snellius, including a HNLMS Snellius (A802), currently-serving vessel. Biography Willebrord Snellius was born in Leiden, Netherlands. In 1613 he succeeded his father, Rudolph Snellius, Rudolph Snel van Royen (1546–1613) as professor of mathematics at the University of Leiden. Surveying In 1615, Snellius, after the work of Eratosthenes in Ptolemaic Kingdom, Ptolemaic Egypt in the 3rd century BC, probably was the first to use triangulation (surveying), triangulation to do a large-scale arc measurement for determining the Earth radius, circumference of the earth. He was helped in his measureme ...
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Mare Fecunditatis
Mare Fecunditatis (Latin ''fēcunditātis'', the "Sea of Fecundity" or "Sea of Fertility") is a lunar mare in the eastern half of the visible Moon. The mare has a maximum diameter of 840 km. __NOTOC__ Description The Fecunditatis basin formed in the Pre-Nectarian epoch, while the basin material surrounding the mare is of the subsequent Nectarian epoch. The mare material is of the Upper Imbrian epoch and is relatively thin compared to the neighboring Mare Crisium or Mare Tranquillitatis. This basin is overlapped with the Nectaris, Tranquillitatis, and Crisium basins. Fecunditatis basin meets Nectaris basin along Fecunditatis' western edge, with the area along this zone faulted by arcuated grabens. On the eastern edge of Fecunditatis is the crater Langrenus. Near the center lie the interesting craters Messier and Messier A. It was here that the first automated sample return took place via the Luna 16 probe, in September 1970. Sinus Successus lies along the eastern edge of t ...
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Stevinus (crater)
Stevinus is a lunar impact crater located in the southeast part of the Moon. To the southeast is the large crater Furnerius. Just to the northeast is Snellius and the Vallis Snellius crater valley. To the west-northwest lies Reichenbach. To the west-northwest of Stevinus is the tiny crater Stevinus A, a feature that possesses a small ray system and a displays a high albedo. Stevinus has a high inner wall and a central peak at the midpoint of the interior floor. The inner walls are slumped, so that the side slopes down sharply, then more gradually. There are several small ridges on the floor, in addition to the peak. Due to its ray system, Stevinus 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 Systemonline It is named for Simon Stevin, a 16th-century Belgian mathematician and engineer. File:Stevinus (LRO).png, LR ...
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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 ...
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Petavius (crater)
Petavius is a large lunar impact crater located to the southeast of the Mare Fecunditatis, near the southeastern lunar limb. Attached to the northwest rim is the smaller crater Wrottesley. To the southeast are Palitzsch, Vallis Palitzsch, and Hase. Farther to the north is the large crater Vendelinus. Petavius appears oblong when viewed from the Earth due to foreshortening. Petavius is Imbrian in age. The outer wall of Petavius is unusually wide in proportion to the diameter, and displays a double rim along the south and west sides. The height of the rim varies by as much as 50% from the lowest point, and a number of ridges radiate outwards from the rim. The convex crater floor has been resurfaced by lava flow, and displays a rille system named the Rimae Petavius. The large central mountains are a prominent formation with multiple peaks, climbing 1.7 kilometers above the floor. A deep fracture runs from the peaks toward the southwest rim of the crater. Rev. T. W. Webb desc ...
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