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Østervold Observatory
Østervold Observatory (or Copenhagen University Observatory; da, Københavns Universitet Astronomisk Observatorium) is a former astronomical observatory (IAU code 035) in Copenhagen, Denmark owned and operated by the University of Copenhagen (Københavns Universitet). It opened in 1861 as a replacement for the University's old observatory at Rundetårn. History The first astronomical observatory operated by the University of Copenhagen was Rundetårn. It had been inaugurated in 1642 as a replacement for Tycho Brahe's Stjerneborg, but during the early 19th century had become outdated as astronomical instruments grew bigger and bigger while the tower could not be expanded. In the same time, light pollution from the surrounding city as well as vibrations caused by the still increasing traffic in the streets below had made the observations inaccurate. In 1861 the observatory was moved to Østervold, where a new observatory was constructed on the old bastioned fortifications of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Egyptian astronomy, Egyptians, Chinese astronomy, Chinese, Maya civilization, Maya, and many anc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Star
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ejnar Hertzsprung
Ejnar Hertzsprung (; Copenhagen, 8 October 1873 – 21 October 1967, Roskilde) was a Danish chemist and astronomer. Career Hertzsprung was born in Frederiksberg, Denmark, the son of Severin and Henriette. He studied chemical engineering at Copenhagen Polytechnic Institute, graduating in 1898. After spending two years working as a chemist in St. Petersburg, in 1901 he studied photochemistry at Leipzig University for a year. His father was an amateur astronomy, which led to Ejnar's interest in the subject. He began making astronomical observations in Fredericksberg in 1902, and within a few years had noticed that stars with similar spectral type could have widely different absolute magnitudes. In 1909, he took a position at the Göttingen Observatory under director Karl Schwarzschild. In 1911 Hertzsprung developed the Hertzsprung–Russell diagram, independently developed in 1913 by Henry Norris Russell. In 1913 Hertzsprung determined the distances to several Cepheid variable st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertzsprung–Russell Diagram
The Hertzsprung–Russell diagram, abbreviated as H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosity, luminosities versus their stellar classifications or effective temperatures. The diagram was created independently in 1911 by Ejnar Hertzsprung and by Henry Norris Russell in 1913, and represented a major step towards an understanding of stellar evolution. Historical background In the nineteenth century large-scale photographic spectroscopic surveys of stars were performed at Harvard College Observatory, producing spectral classifications for tens of thousands of stars, culminating ultimately in the Henry Draper Catalogue. In one segment of this work Antonia Maury included divisions of the stars by the width of their spectral lines. Hertzsprung noted that stars described with narrow lines tended to have smaller proper motions than the others of the same spectral classification. He took this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Structure
Stellar structure models describe the internal structure of a star in detail and make predictions about the luminosity, the color and the future evolution of the star. Different classes and ages of stars have different internal structures, reflecting their elemental makeup and energy transport mechanisms. Energy transport Different layers of the stars transport heat up and outwards in different ways, primarily convection and radiative transfer, but thermal conduction is important in white dwarfs. Convection is the dominant mode of energy transport when the temperature gradient is steep enough so that a given parcel of gas within the star will continue to rise if it rises slightly via an adiabatic process. In this case, the rising parcel is buoyant and continues to rise if it is warmer than the surrounding gas; if the rising parcel is cooler than the surrounding gas, it will fall back to its original height. In regions with a low temperature gradient and a low enough opacity to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bengt Strömgren
Bengt Georg Daniel Strömgren (21 January 1908 – 4 July 1987) was a Danish astronomer and astrophysicist. Life and career Bengt Strömgren was born in Gothenburg. His parents were Hedvig Strömgren (née Lidforss) and Elis Strömgren, who was professor of astronomy at the University of Copenhagen and director of the University Observatory in Copenhagen. Bengt grew up in the professor's mansion surrounded with scientists, assistants, observers and guests. His father paced and promoted Bengt into a life with science, and Bengt's first paper was published already at the age of 14. He graduated from high school in 1925 and enrolled at the Copenhagen university. Only two years later, he graduated in astronomy and atomic physics, and during the following two years, he completed a doctoral degree, which was evaluated with the best marks in December 1929, when he was 21 years old. He gained a great deal of useful experience from his studies in theoretical physics at Niels Bohr's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge, Massachusetts
Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, Worcester, and Springfield. It is one of two de jure county seats of Middlesex County, although the county's executive government was abolished in 1997. Situated directly north of Boston, across the Charles River, it was named in honor of the University of Cambridge in England, once also an important center of the Puritan theology embraced by the town's founders. Harvard University, the Massachusetts Institute of Technology (MIT), Lesley University, and Hult International Business School are in Cambridge, as was Radcliffe College before it merged with Harvard. Kendall Square in Cambridge has been called "the most innovative square mile on the planet" owing to the high concentration of successful startups that have emerged in the vicinity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smithsonian Astrophysical Observatory
The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution, concentrating on astrophysical studies including galactic and extragalactic astronomy, cosmology, solar, earth and planetary sciences, theory and instrumentation, using observations at wavelengths from the highest energy gamma rays to the radio, along with gravitational waves. Established in Washington, D.C., in 1890, the SAO moved its headquarters in 1955 to Cambridge, Massachusetts, where its research is a collaboration with the Harvard College Observatory (HCO) and the Harvard University Department of Astronomy. In 1973, the Smithsonian and Harvard formalized the collaboration as the Center for Astrophysics , Harvard & Smithsonian (CfA) under a single Director. History Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kiel
Kiel () is the capital and most populous city in the northern Germany, German state of Schleswig-Holstein, with a population of 246,243 (2021). Kiel lies approximately north of Hamburg. Due to its geographic location in the southeast of the Jutland peninsula on the southwestern shore of the Baltic Sea, Kiel has become one of Germany's major maritime centres, known for a variety of international sailing events, including the annual Kiel Week, which is the biggest sailing event in the world. Kiel is also known for the Kiel mutiny, Kiel Mutiny, when sailors refused to board their vessels in protest against Germany's further participation in World War I, resulting in the abdication of the Wilhelm II, German Emperor, Kaiser and the formation of the Weimar Republic. The Olympic sailing competitions of the 1936 Summer Olympics, 1936 and the 1972 Summer Olympics#Venues, 1972 Summer Olympics were held in the Bay of Kiel. Kiel has also been one of the traditional homes of the German Nav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomische Gesellschaft
__NOTOC__ The ''Astronomische Gesellschaft'' is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society. In 1882, the ''Astronomische Gesellschaft'' founded the Central Bureau for Astronomical Telegrams at Kiel, where it remained until during World War I when it was moved to the Østervold Observatory at Copenhagen, Denmark, to be operated there by the Copenhagen University Observatory. Around the turn of the 20th century the A.G. initiated the most important star catalog of this time, the ''Astronomische Gesellschaft Katalog'' (AGK). The assembly in Danzig (now Gdańsk) in August 1939 was the last until a meeting at Göttingen in 1947, when it was re-commenced as ''Astronomische Gesellschaft in der Britischen Zone''. The post-war editorial board consisted of Chairman Albrecht Unsöld (Kiel), Otto Heckmann, J. Larink, B. Straßl, Paul ten Bruggencate, and also Max Beyer representing the amateurs of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Bureau For Astronomical Telegrams
The Central Bureau for Astronomical Telegrams (CBAT) is the official international clearing house for information relating to transient astronomical events. The CBAT collects and distributes information on comets, natural satellites, novae, supernovae and other transient astronomical events. CBAT also establishes priority of discovery (who gets credit for it) and assigns initial designations and names to new objects. On behalf of the International Astronomical Union (IAU), the CBAT distributes ''IAU Circulars''. From the 1920s to 1992, CBAT sent telegrams in urgent cases, although most circulars were sent via regular mail; when telegrams were dropped, the name "telegram" was kept for historical reasons, and they continued as the ''Central Bureau Electronic Telegrams''. Since the mid-1980s the ''IAU Circulars'' and the related '' Minor Planet Circulars'' have been available electronically. The CBAT is a non-profit organization, but charges for its ''IAU Circulars'' and electronic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
