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John Charles Duncan
John Charles Duncan (February 8, 1882 in Knightstown, Indiana – September 10, 1967 in Chula Vista, California) was an American astronomer. Life John Charles Duncan was the son of Daniel Davidson and Naomi, née Jessup, Duncan. He graduated from Indiana University and received his Bachelor of Arts there in 1905. In 1905/1906, he received the first Lawrence Fellowship donated by Percival Lowell to students of Indiana University at the Lowell Observatory in Flagstaff, Arizona, and participated in the photographic search for Trans-Neptunian planets. In the summer of 1912 he returned to the Lowell Observatory to help with the search. After receiving his Master of Arts in 1906, he began his doctoral studies at the University of California under the director of the Lick Observatory William Wallace Campbell, and in 1909 defended his dissertation on the Cepheids Y Sagittarii and RT Aurigae. Duncan was a lecturer at Harvard University from 1909 to 1916, and from 1911 until 1916 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knightstown, Indiana
Knightstown is a town in Wayne Township, Henry County, Indiana, adjacent to Rush County, along the Big Blue River. The population was 2,182 at the 2010 census. It is approximately thirty-two miles east of Indianapolis. Knightstown is famous for the 1986 film '' Hoosiers''. The Hoosier Gym was used in the filming of the film. Knightstown hosts two annual festivals: Jubilee Days held in early-mid June and The Hoosier Fall Festival held in September. Knightstown also hosts an annual car show and a music series on the town square. The Hoosier Gym also hosts Indiana's best high school basketball players in the annual Hoosier Classic. History Knightstown was founded and platted by Waitsell M. Cary in 1827. It was named for Jonathan Knight, an engineer on the National Road and U.S. Congressman from Pennsylvania. A post office has operated in Knightstown since 1833. The Elias Hinshaw House, Knightstown Academy, and Knightstown Historic District are listed on the National Regis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagstaff, Arizona
Flagstaff ( ) is a city in, and the county seat of, Coconino County, Arizona, Coconino County in northern Arizona, in the southwestern United States. In 2019, the city's estimated population was 75,038. Flagstaff's combined metropolitan area has an estimated population of 139,097. Flagstaff lies near the southwestern edge of the Colorado Plateau and within the San Francisco volcanic field, along the western side of the largest contiguous Pinus ponderosa, ponderosa pine forest in the continental United States. The city sits at about and is next to Mount Elden, just south of the San Francisco Peaks, the highest mountain range in the state of Arizona. Humphreys Peak, the highest point in Arizona at , is about north of Flagstaff in Kachina Peaks WildernessThe geology of the Flagstaff areaincludes abundant volcanic rocks associated with the San Francisco Volcanic Field that range in age from late Miocene to late Holocene. It also includes exposed rock from the Mesozoic and Paleozoic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab Nebula
The Crab Nebula (catalogue designations Messier object, M1, New General Catalogue, NGC 1952, Taurus (constellation), Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus (constellation), Taurus. The common name comes from William Parsons, 3rd Earl of Rosse, who observed the object in 1842 using a telescope and produced a drawing that looked somewhat like a crab. The nebula was discovered by English astronomer John Bevis in 1731, and it corresponds with SN 1054, a bright supernova recorded by Chinese astronomy, Chinese astronomers in 1054. The nebula was the first astronomical object identified that corresponds with a historical supernova explosion. At an apparent magnitude of 8.4, comparable to that of Titan (moon), Saturn's moon Titan, it is not visible to the naked eye but can be made out using binoculars under favourable conditions. The nebula lies in the Perseus Arm of the Milky Way galaxy, at a distance of about from Earth. It has a diame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nebulae
A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions, the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter, and eventually will become dense enough to form stars. The remaining material is then thought to form planets and other planetary system objects. Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxies
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many are thought to have supermassive black holes at their centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Wilson Observatory
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908. It also contains the Snow solar telescope completed in 1905, the 60 foot (18 m) solar tower completed in 1908, the 150 foot (46 m) solar tower completed in 1912, and the CHARA array, built by Georgia State University, which became fully operational in 2004 and was the largest optical interferometer in the world at its completion. Due to the inversion layer that traps warm air and smog over Los Angeles, Mount Wilson has steadier air than any other location in Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steward Observatory
Steward Observatory is the research arm of the Department of Astronomy at the University of Arizona (UArizona). Its offices are located on the UArizona campus in Tucson, Arizona (US). Established in 1916, the first telescope and building were formally dedicated on April 23, 1923. It now operates, or is a partner in telescopes at five mountain-top locations in Arizona, one in New Mexico, one in Hawaii, and one in Chile. It has provided instruments for three different space telescopes and numerous terrestrial ones. Steward also has one of the few facilities in the world that can cast and figure the very large primary mirrors used in telescopes built in the early 21st century. History Steward Observatory owes its existence to the efforts of American astronomer and dendrochronologist Andrew Ellicott Douglass. In 1906, Douglass accepted a position as Assistant Professor of Physics and Geography at the University of Arizona in Tucson, Arizona. Almost immediately upon his arrival ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitin Observatory
Whitin Observatory is an astronomical observatory owned and operated by Wellesley College. Built in 1900, with additions in 1906, 1967, and 2010, it is located in Wellesley, Massachusetts and named after Wellesley College trustee Mrs. John Crane Whitin (Sarah Elizabeth Whitin) of Whitinsville, who donated the funds for the observatory. Astronomer Sarah Frances Whiting was the first director of the new Wellesley College Astronomy Department. The facilities include a 0.7m PlaneWave CDK700 reflector, a 12" Fitz/Clark refractor, a 6" Alvan Clark refractor, a Hale Spectrohelioscope, and Meade 8" SCTs. History In 1896, Wellesley College physics professor Sarah Frances Whiting met trustee Sarah Elizabeth Whitin at a traditional college ceremony, "Float Night." The conversation turned to a 12" refracting telescope Whiting had used that was being offered for sale, and as told in Wellesley College 1875–1975: A Century of Women: Whiting used the telescope in teaching her cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RT Aurigae
RT Aurigae (RT Aur, 48 Aurigae) is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth. RT Aurigae is an F to G type Classical Cepheid variable which varies from magnitude +5.00 to +5.82 with a period of 3.728309 days. The variability was discovered in 1905. It was quickly recognised as a member of the class of Cepheid variables, but their nature was not understood at that time. Radial velocity changes were detected corresponding to the brightness variations, but the idea that these were caused by stellar pulsations and temperature changes was largely dismissed in favour of orbital motions of a binary star. More accurate observations eventually proved beyond doubt that the brightness variations were caused by pulsations in the atmospheres of the stars, with the stars being smallest and hottest near maximum brightness. RT Aurigae has been suspected to be a spectroscopic binary system, but this has not been confirmed. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Sagittarii
Y Sagittarii is a variable star in the constellation of Sagittarius. It is a Cepheid variable with an apparent magnitude that ranges around +5.77. The measure of its parallax by Hubble Space Telescope puts Y Sagittarii to 1,293 light-years away from the Solar System. The brightness ranges in Y Sagittarii's apparent magnitude varies from +5.25 and +6.24 in a period of 5.7736 days. The spectral type of this star is F8II, while the effective temperature is 5370 K. It has a radius 50 times larger than the Sun, while its projected rotational velocity of 16 km / s and it has an estimated mass six times that of the Sun. The star's metal content is similar to Sun, with an index of metallicity e / H= +0.05. For other metals tested, it shows some overabundance of copper, zinc, yttrium and sodium; the level of the elements is almost double that of the Sun ( a / H= +0.27). There is evidence that Y Sagittarii may be a spectroscopic binary. It has been suggested that the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cepheids
A Cepheid variable () is a type of star that Instability strip, pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable frequency, period and amplitude. A strong direct period-luminosity relation, relationship between a Cepheid variable's luminosity and periodic function, pulsation period established Cepheids as important Cosmic distance ladder#Galactic distance indicators, indicators of cosmic benchmarks for scaling cosmic distance ladder, galactic and extragalactic distances. This robust characteristic of classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt after studying thousands of variable stars in the Magellanic Clouds. This discovery allows one to know the true luminosity of a Cepheid by simply observing its pulsation period. This in turn allows one to determine the distance to the star, by comparing its known luminosity to its observed brightness. The term ''Cepheid'' originates from Delta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Wallace Campbell
William Wallace Campbell (April 11, 1862 – June 14, 1938) was an American astronomer, and director of Lick Observatory from 1901 to 1930. He specialized in spectroscopy. He was the tenth president of the University of California from 1923 to 1930. Biography He was born on a farm in Hancock County, Ohio, the son of Robert Wilson and Harriet Welsh Campbell. After a few years of local schooling he entered in 1882 the University of Michigan to study civil engineering, graduating Bachelor of Science in 1886. Whilst at university he developed his interest in astronomy when he read Simon Newcomb's ''Popular Astronomy''. After graduating he was appointed Professor of Mathematics at the University of Colorado but soon moved back to Michigan as an instructor in astronomy. In 1891 he was invited to work on spectroscopy at Lick Observatory in California. Campbell was a pioneer of astronomical spectroscopy and catalogued the radial velocities of stars. He was also recognized for his work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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