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Düsseldorf-Bilk Observatory
The Sternwarte Düsseldorf (a.k.a. Sternwarte Bilk, Sternwarte Charlottenruhe; Bilk Observatory or Düsseldorf-Bilk Observatory in English) in Düsseldorf-Bilk was a private observatory founded in 1843 by Johann Friedrich Benzenberg. The observatory's main feature was a refracting telescope with 1800mm focal length. After Benzenberg's death the observatory was bequeathed to the city of Düsseldorf. It was destroyed by bombing in 1943. Between 1852 and 1890, C. Robert Luther discovered 24 asteroids there, from Thetis, discovered on April 17, 1852, to Glauke, discovered February 20, 1890. These asteroids and planetoids are called ''the 24 Düsseldorf planets''. The asteroid 4425 Bilk is named in honour of the observatory. Near its original location, a benchmark was erected, displaying the observatory's burnt-out telescope. File:bst-close.jpg, Benchmark File:bst-durch.jpg, view through the tube File:bst-dist.jpg, front view File:bst-schild.jpg, information plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Düsseldorf-Bilk
Bilk is a quarter (''Stadtteil'') of Düsseldorf. Together with Düsseldorf-Oberbilk, Oberbilk, Düsseldorf-Unterbilk, Unterbilk, Düsseldorf-Hamm, Hamm, Düsseldorf-Flehe, Flehe and Volmerswerth it constitutes Borough 3 (Düsseldorf), Borough 3, which is the most populous borough of Düsseldorf. Bilk has an area of , and 41,150 inhabitants (2020). Heinrich-Heine-University is in Bilk. History The first documentary mention of Bilk is in the year 799. The Old Church is older and seems to be from about 700 A.D., given by Saint Suitbert, but was destroyed by fire about 900, and is mentioned in 1019 for the first time. During the following centuries, the church was reconstructed frequently, especially in the 12th century and the 17th century. Until the year 1206 the fishing settlement ''dusseldorp'', located to the North of Bilk, belonged to the Bilk parish. After August 14 of 1288 (the Battle of Worringen) Düsseldorf got City Rights, the Old Bilk Church became a city church. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Benzenberg
Johann Friedrich Benzenberg (5 May 1777 – 7 June 1846) was a German astronomer, geologist, and physicist. Biography Benzenberg was born near Elberfeld, Germany on 5 May 1777 to Heinrich Benzenberg and Johanna Elisabeth. He married Charlotte Platzhoff in 1807. After studying theology at Herborn and Marburg, he travelled to Göttingen where he became interested in science through attending lectures by Georg Christoph Lichtenberg and Abraham Gotthelf Kästner. Benzenberg obtained a PhD from the University of Duisburg in 1800 and became a professor of mathematics at the women's college of Düsseldorf in 1805. After the Napoleonic occupation of Germany he immigrated to Switzerland where he became interested in politics. Benzenberg's interest in politics led him to write extensively on issues such as the constitution of Prussia. In 1844 Benzenberg built a private observatory, the Düsseldorf-Bilk Observatory, in Bilk, which he later donated to the city along with a grant to pay for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refracting Telescope
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope design was originally used in spyglasses and astronomy, astronomical telescopes but is also used for long-focus lens, long-focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the reflecting telescope, which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece. Refracting telescopes typically have a lens at the front, then a optical train, long tube, then an eyepiece or instrumentation at the rear, where the telescope view comes to focus. Originally, telescopes had an objective of one element, but a century later, tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower opti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Historically, observatories were as simple as containing an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena). Astronomical observatories Astronomical observatories are mainly divided into four categories: space-based, airborne, ground-based, and underground-based. Ground-based observatories Ground-based observatories, located on the surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum. Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Düsseldorf
Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in the state and the seventh-largest city in Germany, with a population of 617,280. Düsseldorf is located at the confluence of two rivers: the Rhine and the Düssel, a small tributary. The ''-dorf'' suffix means "village" in German (English cognate: ''thorp''); its use is unusual for a settlement as large as Düsseldorf. Most of the city lies on the right bank of the Rhine. Düsseldorf lies in the centre of both the Rhine-Ruhr and the Rhineland Metropolitan Region. It neighbours the Cologne Bonn Region to the south and the Ruhr to the north. It is the largest city in the German Low Franconian dialect area (closely related to Dutch). Mercer's 2012 Quality of Living survey ranked Düsseldorf the sixth most livable city in the world. Düsse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thetis (asteroid)
Thetis, minor planet designation 17 Thetis, is a stony asteroid from the inner regions of the asteroid belt, approximately 90 kilometers in diameter. It was discovered on 17 April 1852, by German astronomer Robert Luther at Bilk Observatory in Düsseldorf, Germany who deferred to Friedrich Wilhelm August Argelander the naming his first asteroid discovery after Thetis from Greek mythology. Description The asteroid orbits the Sun at a distance of 2.1–2.8 AU once every 3 years and 11 months (1,419 days). Its orbit has an eccentricity of 0.13 and an inclination of 6 ° with respect to the ecliptic. The spectrum of this object indicates that it is an S-type asteroid with both low and high calcium forms of pyroxene on the surface, along with less than 20% olivine. The high-calcium form of pyroxene forms 40% or more of the total pyroxene present, indicating a history of igneous rock deposits. This suggests that the asteroid underwent differentiation by melting, creating a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
288 Glauke
Glauke ( minor planet designation: 288 Glauke) is a stony, tumbling asteroid and slow rotator from the intermediate asteroid belt, approximately 32 kilometers in diameter. It was discovered on 20 February 1890, by Robert Luther at Düsseldorf-Bilk Observatory in Germany. It was the last of his asteroid discoveries. It is named after Creusa (known as Glauce or Glauke), a daughter of Creon a king of Corinth in Greek mythology. ''Glauke'' has an exceptionally slow rotation period of about 1200 hours (50 days). This makes it one of the slowest-rotating asteroids in the Solar System. The rotation is believed to be " tumbling", similar to the near-Earth asteroid 4179 Toutatis. It is a common, stony S-type asteroid in both the Tholen and SMASS classification An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetoid
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor planet'', but that year's meeting reclassified minor planets and comets into dwarf planets and small Solar System bodies (SSSBs).Press release, IAU 2006 General Assembly: Result of the IAU Resolution votes International Astronomical Union, August 24, 2006. Accessed May 5, 2008. Minor planets include asteroids ( |
4425 Bilk
44 may refer to: * 44 (number) * one of the years 44 BC, AD 44, 1944, 2044 Military *44M Tas, a Hungarian medium/heavy tank design of World War II *44M Tas Rohamlöveg, a Hungarian tank destroyer design of World War II, derived from the 44M Tas tank Others *"Forty-Four", a blues standard *Forty-Fours, a group of islands in the Chatham Archipelago *Forty Four, Arkansas, an unincorporated community in Izard County, Arkansas * ''44'' (album), a 2020 quadruple album by Joel Plaskett *"44", a song by Bad Gyal featuring Rema from '' Warm Up'' *"Forty Four", a song by Karma to Burn from '' Appalachian Incantation'' *.44 caliber, a family of firearms and firearm cartridges **.44 Special The .44 Smith & Wesson Special, also commonly known as .44 S&W Special, .44 Special, .44 Spl, .44 Spc, (pronounced "forty-four special"), or 10.9x29mmR is a smokeless powder center fire metallic revolver cartridge developed by Smith & Wesson in 1 ..., a revolver cartridge ** .44 Magnum, a large revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 includes a final year of operation for many observatories that are no longer in operation. While other sciences, such as volcanology and meteorology, also use facilities called observatories for research and observations, this list is limited to observatories that are used to observe celestial objects. Astronomical observatories are mainly divided into four categories: space-based, airborne, ground-based, and underground-based. Many modern telescopes and observatories are located in space to observe astronomical objects in wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere (such as ultraviolet radiation, X-rays, and gamma rays) and are thus impossible to observe using ground-based telescopes. Being above the atmosphere, these space observatories can also avoid the effects of atmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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