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1009 Sirene
Sirene ( minor planet designation: 1009 Sirene), provisional designation , is an eccentric asteroid and sizable Mars-crosser from the central regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory on 31 October 1923. The asteroid was named after the Siren from Greek mythology. Orbit and classification ''Sirene'' is a Mars-crossing asteroid with a notably large semi-major axis is 2.62  AU, due to its high eccentricity of 0.46. It orbits the Sun in the central main-belt at a distance of 1.4–3.8  AU once every 4 years and 3 months (1,552 days). Its orbit has an inclination of 16 ° with respect to the ecliptic. The body's observation arc begins 9 days after its official discovery observation at Bergedorf Observatory in Hamburg. On 8 June 1949, ''Sirene'' passed from Mars. Aethra group and mass of Mars ''Sirene'' had been of great interest in 1 ...
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Karl Reinmuth
Karl Wilhelm Reinmuth (4 April 1892 in Heidelberg – 6 May 1979 in Heidelberg) was a German astronomer and a prolific discoverer of 395 minor planets. Scientific career From 1912 to 1957, Reinmuth was working as an astronomer at the Heidelberg Observatory (german: Landessternwarte Heidelberg-Königstuhl) an astronomical observatory on the Königstuhl hill above Heidelberg in southern Germany. He was a member at the minor planet studies group at Astronomisches Rechen-Institut between 1947 and 1950, and later became "Oberobservator" or chief-observer at Heidelberg Observatory until his retirement in 1957. Reinmuth obtained more than 12,500 precise astrometric measurements of minor planets' positions on photographic plates, an enormous accomplishment before computer-based assistance existed. Honours The outer main-belt asteroid 1111 Reinmuthia, discovered by himself at Heidelberg in 1912, was named in his honour (). Discoveries Among his most notable discoveries are ...
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Kirkwood Gap
A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter. For example, there are very few asteroids with semimajor axis near 2.50 AU, period 3.95 years, which would make three orbits for each orbit of Jupiter (hence, called the 3:1 orbital resonance). Other orbital resonances correspond to orbital periods whose lengths are simple fractions of Jupiter's. The weaker resonances lead only to a depletion of asteroids, while spikes in the histogram are often due to the presence of a prominent asteroid family ''(see List of asteroid families)''. The gaps were first noticed in 1866 by Daniel Kirkwood, who also correctly explained their origin in the orbital resonances with Jupiter while a professor at Jefferson College in Canonsburg, Pennsylvania. Most of the Kirkwood gaps are depleted, unlike the mean-motion resonanc ...
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Lightcurve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequency interval or band. Light curves can be periodic, as in the case of eclipsing binaries, Cepheid variables, other periodic variables, and transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it. Variable stars Graphs of the apparent magnitude of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their ...
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Turku Observatory
Turku ( ; ; sv, Åbo, ) is a city and former capital on the southwest coast of Finland at the mouth of the Aura River, in the region of Finland Proper (''Varsinais-Suomi'') and the former Turku and Pori Province (''Turun ja Porin lääni''; 1634–1997). The region was originally called Suomi (Finland), which later became the name for the whole country. As of 31 March 2021, the population of Turku was 194,244 making it the sixth largest city in Finland after Helsinki, Espoo, Tampere, Vantaa and Oulu. There were 281,108 inhabitants living in the Turku Central Locality, ranking it as the third largest urban area in Finland after the Capital Region area and Tampere Central Locality. The city is officially bilingual as percent of its population identify Swedish as a mother-tongue. It is unknown when Turku gained city rights. The Pope Gregory IX first mentioned the town ''Aboa'' in his ''Bulla'' in 1229 and the year is now used as the foundation year of Turku. Turku is th ...
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Perihelion And Aphelion
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elliptic orbit. The name for each apsis is created from the prefixes ''ap-'', ''apo-'' (), or ''peri-'' (), each referring to the farthest and closest point to the primary body the affixing necessary suffix that describes the primary body in the orbit. In this case, the suffix for Earth is ''-gee'', so the apsides' names are ''apogee'' and ''perigee''. For the Sun, its suffix is ''-helion'', so the names are ''aphelion'' and ''perihelion''. According to Newton's laws of motion, all periodic orbits are ellipses. The barycenter of the two bodies may lie well within the bigger body—e.g., the Earth–Moon barycenter is about 75% of the way from Earth's center to its surface. If, compared to the larger mass, the smaller mass is negligible (e.g., ...
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Opposition (planets)
In positional astronomy, two astronomical objects are said to be in opposition when they are on opposite sides of the celestial sphere, as observed from a given body (usually Earth). A planet (or asteroid or comet) is said to be "in opposition" or "at opposition" when it is in opposition to the Sun. Because most orbits in the Solar System are nearly coplanar to the ecliptic, this occurs when the Sun, Earth, and the body are configured in an approximately straight line, or syzygy; that is, Earth and the body are in the same direction as seen from the Sun. Opposition occurs only for superior planets (see the diagram). The instant of opposition is defined as that when the apparent geocentric celestial longitude of the body differs by 180° from the apparent geocentric longitude of the Sun. At that time, a body is: * in apparent retrograde motion * visible almost all night – rising around sunset, culminating around midnight, and setting around sunrise * at the point in i ...
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132 Aethra
Aethra ( minor planet designation: 132 Aethra) is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It measures approximately 40 kilometers in diameter. It was discovered by James Craig Watson in 1873 and is the first such Mars-crosser asteroid to be identified. As a Mars-crosser asteroid, Aethra is the lowest numbered asteroid to not have proper orbital elements due to recurring perturbations by Mars. It has a rather eccentric orbit that sometimes brings it closer to the Sun than the planet Mars. With an original observation arc of only 22 days, 132 Aethra was a lost asteroid between 1873 and 1922. The varying light curve of the asteroid implies an elongated or irregular shape for its body. It is named after Aethra, the mother of Theseus in Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern ...
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Yerkes Observatory
Yerkes Observatory ( ) is an astronomical observatory located in Williams Bay, Wisconsin, United States. The observatory was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 to 2018. Ownership was transferred to the non-profit Yerkes Future Foundation (YFF) in May 2020, which began restoration and renovation of the historic building and grounds. Re-opening for public tours and programming began May 27, 2022. The observatory, often called "the birthplace of modern astrophysics," was founded in 1892 by astronomer George Ellery Hale and financed by businessman Charles T. Yerkes. It represented a shift in the thinking about observatories, from their being mere housing for telescopes and observers, to the early-20th-century concept of observation equipment integrated with laboratory space for physics and chemistry analysis. The observatory's main dome houses a doublet lens refracting telescope, the largest refractor ever su ...
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Vienna Observatory
The Vienna Observatory (german: Universitätssternwarte Wien) is an astronomical observatory in Vienna, Austria. It is part of the University of Vienna. The first observatory was built in 1753–1754 on the roof of one of the university buildings. A new observatory was built between 1874 and 1879, and was finally inaugurated by Emperor Franz Joseph I of Austria in 1883. The main dome houses a refractor with a diameter of and a focal length of built by the Grubb Telescope Company. At that time, it was the world's largest refracting telescope. Land for the new observatory was purchased in 1872, and was noted for having increased elevations (about 150 ft) above the city. Construction started in March 1874, and it was opened with new instruments in 1877. The overall design had various rooms and three main domes, one for the Grubb refractor and then two smaller domes, and some terraces. At this time there were larger aperture reflecting telescopes, and the main technologies ...
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Brera Astronomical Observatory
The Brera Observatory ( it, Osservatorio Astronomico di Brera) is an astronomical observatory in the Brera district of Milan, Italy. It was built in the historic Palazzo Brera in 1764 by the Jesuit astronomer Roger Boscovich. Following the suppression of the Jesuits by Clement XIV on 21 July 1773, the palace and the observatory passed to the then rulers of northern Italy, the Austrian Habsburg dynasty. From 1 December 1786, the Austrian Empire adopted “transalpine time”. The astronomers were engaged by Count Giuseppe Di Wilczek, the plenipotentiary governor of Lombardy, to build a meridian line inside Milan Cathedral. It was constructed by Giovanni Angelo Cesaris and Francesco Reggio, with Roger Joseph Boscovich acting as a consultant. Following the independence of Italy in 1861, the observatory has been run by the Italian government. In 1862, the newly installed Italian government improved the observatory's facilities by commissioning a 218mm Merz Equatorial Refracting T ...
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Algiers Observatory
The Algiers Observatory was built in the late 19th century in the Algiers suburb of Bouzaréah, Algeria, North Africa. It participated in the Astrographic Catalogue project, taking the zone between -2 and +4 degrees to expose 1,260 plates between the years 1891 and 1911. At the tail end of that time, the director of the installation was François Gonnessiat. It is now known as the Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG), where it combines astronomy with work in astrophysics, and geophysical research, including the monitoring of earthquakes. Astronomers Astronomers who worked at the observatory include: * Alfred Schmitt * Benjamin Jekhowsky * Frédéric Sy * Guy Reiss * Joanny-Philippe Lagrula * Louis Boyer * Odette Bancilhon See also * List of astronomical observatories This is a list of astronomical observatories ordered by name, along with initial dates of operation (where an accurate date is available) and location. The list also ...
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Bergedorf Observatory
Hamburg Observatory (german: Hamburger Sternwarte) is an astronomical observatory located in the Bergedorf borough of the city of Hamburg in northern Germany. It is owned and operated by the University of Hamburg, Germany since 1968, although it was founded in 1825 by the City of Hamburg and moved to its present location in 1912. It has operated telescopes at Bergedorf, at two previous locations in Hamburg, at other observatories around the world, and it has also supported space missions. The largest near-Earth object was discovered at this Observatory by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg on 23 October 1924. That asteroid, 1036 Ganymed is about 20 miles (35 km) in diameter. The Hamburg 1-meter reflector telescope (first light 1911) was one of the biggest telescopes in Europe at that time, and by some measures the fourth largest in the World. The Observatory also has an old style Great Refractor (a ''Großen Refraktor''), a long telescop ...
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