Johann Gottfried Köhler
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Johann Gottfried Köhler
Johann Gottfried Köhler (15 December 1745 – 19 September 1801) was a German astronomer who discovered a number of nebulae, star clusters, and galaxies. Köhler is best remembered for his discovery of Open Cluster M67, Elliptical Galaxy M59, and Elliptical Galaxy M60. The latter two were discovered on the same day, 11 April 1779. He worked with the noted astronomer Johann Elert Bode, who refined and published Köhler's proposal for the symbol of Uranus Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus ( Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars), grandfather of Zeus (Jupiter) and father of .... From 1784 he was the director of Mathematisch-Physikalischer Salon.Klaus Schillinger: ''Johann Gottfried Köhler - Inspektor am Mathematisch-Physikalischen Salon Dresden -aktiver Beobachter des gestirnten Himmels im letzten Viertel des 18. Jahrhunderts''. In: ''Der Meister ...
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Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ...
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Nebula
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 ...
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Star Cluster
Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clustered groups of stars, generally containing fewer than a few hundred members, and are often very young. Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy, but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound; they are then known as a stellar association, sometimes also referred to as a ''moving group''. Star clusters visible to the naked eye include the Pleiades, Hyades, and 47 Tucanae. Open cluster Open clusters are very different from globular clusters. Unlike the spherically distributed globulars, they are confined to the galactic plane, and are almost always found wit ...
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Galaxy
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 o ...
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Open Cluster M67
Messier 67 (also known as M67 or NGC 2682) and sometimes called the King Cobra cluster or the Golden Eye cluster is an open cluster in the southern, equatorial half of Cancer. It was discovered by Johann Gottfried Koehler in 1779. Estimates of its age range between 3.2 and 5 billion years. Distance estimates are likewise varied, but typically are . Estimates of 855, 840, and 815 pc were established via binary star modelling and infrared color-magnitude diagram fitting. Description M67 is not the oldest known open cluster, but there are few Milky Way clusters known to be older, and none of those is closer than M67. It is a paradigm study object in stellar evolution: * it is well-populated * has negligible amounts of dust obscuration * all its stars are at the same distance and age, save for approximately 30 anomalous blue stragglers M67 is one of the most-studied open clusters, yet estimates of its physical parameters such as age, mass, and number of stars of a given type, va ...
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Elliptical Galaxy M59
Messier 59 or M59, also known as NGC 4621, is an elliptical galaxy in the equatorial constellation of Virgo. It is a member of the Virgo Cluster, with the nearest fellow member away and around 5 magnitudes fainter. The nearest cluster member of comparable brightness is the lenticular galaxy NGC 4638, which is around away. It and the angularly nearby elliptical galaxy Messier 60 were both discovered by Johann Gottfried Koehler in April 1779 when observing comet seeming close by. Charles Messier listed both in the Messier Catalogue about three days after Koehler's discovery. This is an elliptical galaxy of type E5 with a position angle of 163.3°, indicating the overall shape shows a flattening of 50%. However, isophotes for this galaxy deviate from a perfect ellipticity, showing pointed shapes instead. These can be decomposed mathematically into a three component model, with each part having a different eccentricity. The main elliptical component appears to be superimposed upo ...
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Elliptical Galaxy M60
Messier 60 or M60, also known as NGC 4649, is an elliptical galaxy approximately 57 million light-years away in the equatorial constellation of Virgo. Together with NGC 4647, it forms a pair known as Arp 116. Messier 60 and nearby elliptical galaxy Messier 59 were discovered by Johann Gottfried Koehler in April 1779, observing a comet in the same part of the sky. Charles Messier added both to his catalogue about three days after this. Characteristics This is an elliptical galaxy of type E (E1.5), although some sources class it as S0 – a lenticular galaxy. An E2 class indicates a flattening of 20%, which has a nearly round appearance. The isophotes of the galaxy are boxy in shape, rather than simple ellipses. The mass-to-light ratio is a near constant 9.5 in the V (visual) band of the UBV system. The galaxy has an effective radius of (translating, at its distance, to about 10 kpc), with an estimated mass of ~1012  within a threefold volume, of which near ...
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Johann Elert Bode
Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career Bode was born in Hamburg. As a youth, he suffered from a serious eye disease that particularly damaged his right eye; he continued to have trouble with his eyes throughout his life. His early promise in mathematics brought him to the attention of Johann Georg Büsch, who allowed Bode to use his own library for study. He began his career with the publication of a short work on the solar eclipse of 5 August 1766. This was followed by an elementary treatise on astronomy entitled ''Anleitung zur Kenntniss des gestirnten Himmels'' (1768, 10th ed. 1844), the success of which led to his being invited to Berlin by Johann Heinrich Lambert in 1772 for the purpose of computing ephemerides on an improved plan. There he founded, in 1774, the well-known ...
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Uranus
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather of Zeus (Jupiter (mythology), Jupiter) and father of Cronus (Saturn (mythology), Saturn). It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as "ice giants" to distinguish them from the other giant planets. As with gas giants, ice giants also lack a well defined "solid surface." Uranus's Atmosphere#Others, atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more "volatiles, ices" such as water, ammonia, and methane, al ...
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Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded on August 10, 1846, it operates as a trust instrumentality and is not formally a part of any of the three branches of the federal government. The institution is named after its founding donor, British scientist James Smithson. It was originally organized as the United States National Museum, but that name ceased to exist administratively in 1967. Called "the nation's attic" for its eclectic holdings of 154 million items, the institution's 19 museums, 21 libraries, nine research centers, and zoo include historical and architectural landmarks, mostly located in the District of Columbia. Additional facilities are located in Maryland, New York, and Virginia. More than 200 institutions and museums in 45 states,States without Smithsonian ...
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Mathematisch-Physikalischer Salon
The Mathematisch-Physikalischer Salon (, ''Royal Cabinet of Mathematical and Physical Instruments'') in Dresden, Germany, is a museum of historic clocks and scientific instruments. Its holdings include terrestrial and celestial globes, astronomical, optical and geodetic devices dating back to the 16th century, as well as historic instruments for calculating and drawing length, mass, temperature and air pressure. Fritz Löffler: ''Das alte Dresden – Geschichte seiner Bauten''. 16th ed. Leipzig: Seemann, 2006, The Mathematisch-Physikalischer Salon is part of the Staatliche Kunstsammlungen Dresden (State Art Collections). It is located in the Zwinger. Today's presentation After a general reconstruction of the Zwinger, the museum has been reopened April 14, 2013. The new exhibition presents about 500 historical scientific instruments. They are shown in four chapters. * ''The Cosmos of the Prince'': Mechanical marvels and mathematical instruments from around 1600. * ' ...
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Springer Publishing
Springer Publishing Company is an American publishing company of academic journals and books, focusing on the fields of nursing, gerontology, psychology, social work, counseling, public health, and rehabilitation (neuropsychology). It was established in 1951 by Bernhard Springer, a great-grandson of Julius Springer, and is based in Midtown Manhattan, New York City. History Springer Publishing Company was founded in 1950 by Bernhard Springer, the Berlin-born great-grandson of Julius Springer, who founded Springer-Verlag (now Springer Science+Business Media). Springer Publishing's first landmark publications included ''Livestock Health Encyclopedia'' by R. Seiden and the 1952 ''Handbook of Cardiology for Nurses''. The company's books soon branched into other fields, including medicine and psychology. Nursing publications grew rapidly in number, as Modell's ''Drugs in Current Use'', a small annual paperback, sold over 150,000 copies over several editions. Solomon Garb's ''Labor ...
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