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Friedrich Wilhelm Argelander
Friedrich Wilhelm August Argelander (22 March 1799 – 17 February 1875) was a German astronomer. He is known for his determinations of stellar brightnesses, positions, and distances. Life and work Argelander was born in Memel in the Kingdom of Prussia (now Klaipėda in Lithuania), the son of a father of Finnish descent, Johann Gottlieb Argelander, and German (Prussian) mother, Dorothea Wilhelmina Grünhagen. He studied with Friedrich Bessel, whose assistant he became in 1820, and obtained his Ph.D. in 1822 at University of Königsberg. From 1823 until 1837, Argelander was the head of the Finnish observatory, first in Turku and then in Helsinki. He then moved to Bonn, Germany. There he designed and built a new observatory at the University of Bonn with funding approved directly by King Frederick William IV whom Argelander had become friends with in his childhood. This lifelong friendship had started when the then crown prince temporarily lived in Argelander's parents hou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klaipėda
Klaipėda ( ; ) is a city in Lithuania on the Baltic Sea coast. It is the List of cities in Lithuania, third-largest city in Lithuania, the List of cities in the Baltic states by population, fifth-largest city in the Baltic States, and the capital of Klaipėda County, as well as the only major seaport in the country – the Port of Klaipėda, which is also the busiest port in the Baltic States. The city has a complex recorded history, partially due to the combined regional importance of the usually ice-free port at the mouth of the river . It was located in Lithuania Minor, and the State of the Teutonic Order and Duchy of Prussia under the suzerainty of the Polish–Lithuanian Commonwealth, then the Kingdom of Prussia and German Empire, within which it was the northernmost big city until it was placed under French occupation in 1919. From 1923, the city was part of Lithuania until its annexation by Nazi Germany in 1939, and after World War II it was part of the Lithuanian Soviet ... [...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, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. The term ''observatoire'' has been used in French since at least 1976 to denote any institution that compiles and presents data on a particular subject (such as public health observatory) or for a particular geographic area (European Audiovisual Observatory). Astronomical observatories Astronomical observatories are mainly divided into four categories: space observatory, space-based, airborne observatory, airborne, ground-based, and underground-based. Historically, ground-based observatories were as simple as containing a mural instrument (for measuring the angle between stars) or Stonehenge (which has some alignments on astronomical phenomena). Ground-based observatories Ground-based observatories, located on the surface of Earth, are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eduard Schönfeld
Eduard Schönfeld (22 December 18281 May 1891) was a German astronomer. Education Schönfeld was born at Hildburghausen, in the Duchy of Saxe-Meiningen, where he had a distinguished career at the gymnasium. On leaving the gymnasium, he desired to devote himself to astronomy, but abandoned the idea in deference to his father's wishes. He went first to Hanover, and afterwards to Kassel to study architecture, for which he seems to have had little inclination. 1849 found him studying chemistry under Bunsen at Marburg, where his love for astronomy was revived by Gerling's lectures. In 1851, he visited the Bonn Observatory and studied astronomy under Friedrich Wilhelm Argelander. In 1853, he was appointed assistant, and in the following year won a doctor's degree with his treatise ''Nova elementa Thetidis''. At Bonn he took an important part in preparing the ''Durchmusterung'' of the northern heavens. He took up the investigation of the light-changes in variable stars, devoting to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adalbert Krüger
Karl Nikolaus Adalbert Krueger (9 December 1832 – 21 April 1896) was a German astronomer. Born in Marienburg, Prussia (now Malbork, Poland), he was editor of '' Astronomische Nachrichten ''from 1881 until his death. Krueger died of a heart condition in Kiel at the age of 63. Life and work In 1851, Krueger entered the University of Berlin where he studied mathematics and science. In 1853, showing a special preference for astronomical studies, Krueger moved to the University of Bonn and became an assistant to the astronomer Friedrich Wilhelm Argelander at the Bonn Observatory. Under Argelander's supervision he produced data for the comprehensive astrometric star catalogue known as the Bonner Durchmusterung, together with fellow student Eduard Schönfeld . Starting in Bonn, he undertook a lifelong study of the orbit of the minor planet Themis, whose perturbations by Jupiter eventually enabled him in 1873 (while at Helsinki Observatory) to determine the mass of the latter pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Motion
Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable reference such as the International Celestial Reference Frame (ICRF). Patterns in proper motion reveal larger structures like stellar streams, the general rotation of the Milky Way disk, and the random motions of stars in the Galactic halo. The components for proper motion in the equatorial coordinate system (of a given epoch, often J2000.0) are given in the direction of right ascension (''μ''α) and of declination (''μ''δ). Their combined value is computed as the ''total proper motion'' (''μ''). It has dimensions of angle per time, typically arcseconds per year or milliarcseconds per year. Knowledge of the proper motion, distance, and radial velocity allows calculations of an object's motion from the Solar System's frame of reference an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groombridge 1830
Groombridge 1830 is a star 29.9 light-years away in the constellation Ursa Major. With an apparent magnitude of 6.4, it is near the limit of naked eye visibility under ideal conditions. It has a low metallicity and is thought to be a superflare star. Discovery and naming The star was catalogued by British astronomer Stephen Groombridge with the Groombridge Transit Circle between 1806 and the 1830s and published posthumously in his star catalog, ''Catalogue of Circumpolar Stars'' (1838). The designation Groombridge 1830 comes from this catalog; in older sources it is sometimes written as 1830 Groombridge. Its high proper motion was noted by Friedrich Wilhelm Argelander in 1842, and so it is sometimes called Argelander's Star, a name first used in an 1853 paper. Other designations for this star include HD 103095, HR 4550, and Gliese 451. It has the variable star designation CF Ursae Majoris, which originally referred to a supposed flaring companion star that is no longer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * ''Intrinsic variables'', whose luminosity actually changes periodically; for example, because the star swells and shrinks. * ''Extrinsic variables'', whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars exhibit at least some oscillation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliometer
A heliometer (from Greek ἥλιος ''hḗlios'' "sun" and ''measure'') is an instrument originally designed for measuring the variation of the Sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use. Description The basic concept is to introduce a split element into a telescope's optical path so as to produce a double image. If one element is moved using a screw micrometer, precise angle measurements can be made. The simplest arrangement is to split the object lens in half, with one half fixed and the other attached to the micrometer screw and slid along the cut diameter. To measure the diameter of the Sun, for example, the micrometer is first adjusted so that the two images of the solar disk coincide (the "zero" position where the split elements form essentially a single element). The micrometer is then adjusted so that diametrically opposite sides of the two images of the solar disk just touc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Napoleonic Wars
{{Infobox military conflict , conflict = Napoleonic Wars , partof = the French Revolutionary and Napoleonic Wars , image = Napoleonic Wars (revision).jpg , caption = Left to right, top to bottom:Battles of Battle of Austerlitz, Austerlitz, Fall of Berlin (1806), Berlin, Battle of Friedland, Friedland, Battle of Aspern-Essling, Aspern-Essling, French occupation of Moscow, Moscow, Battle of Leipzig, Leipzig and Battle of Paris (1814), Paris , date = {{start and end dates, 1803, 5, 18, 1815, 11, 20, df=yes({{Age in years, months, weeks and days, month1=05, day1=18, year1=1803, month2=11, day2=20, year2=1815) , place = Atlantic Ocean, Caucasus, Europe, French Guiana, Mediterranean Sea, North Sea, West Indies, Ottoman Egypt, Egypt, East Indies. , result = Coalition victory , combatant1 = Coalition forces of the Napoleonic Wars, Coalition forces:{{flagcountry, United Kingdom of Great Britain and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Of Jena–Auerstedt
The twin battles of Jena and Auerstedt (; older spelling: ''Auerstädt'') were fought on 14 October 1806 on the plateau west of the river Saale in today's Germany, between the forces of Napoleon I of France and Frederick William III of Prussia, at the outset of the War of the Fourth Coalition during the Napoleonic Wars. The defeat suffered by the Prussian Army subjugated the Kingdom of Prussia to the French Empire until the Sixth Coalition was formed in 1813. Several figures who were later integral to the reformation of the Prussian Army participated at Jena–Auerstedt, including Gebhard von Blücher, Carl von Clausewitz, August Neidhardt von Gneisenau, Gerhard von Scharnhorst, and Hermann von Boyen. Background Following the Prussian declaration of war, Napoleon initiated his campaign against the Fourth Coalition by thrusting a 180,000-strong force through the Franconian Forest. The Prussian army, meanwhile, awaited Napoleon's advance with a force composed of about 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick William IV Of Prussia
Frederick William IV (; 15 October 1795 – 2 January 1861), the eldest son and successor of Frederick William III of Prussia, was King of Prussia from 7 June 1840 until his death on 2 January 1861. Also referred to as the "romanticist on the throne", he was deeply religious and believed that he ruled by divine right. He feared revolutions, and his ideal state was one governed by the Christian estates of the realm rather than a constitutional monarchy. In spite of his conservative political philosophy, he initially pursued a moderate policy of easing press censorship, releasing political prisoners and reconciling with the Catholic population of the kingdom. During the German revolutions of 1848–1849, he was initially forced to accommodate the people's revolutionary sentiments, although he rejected the title of Emperor of the Germans offered by the Frankfurt Parliament in 1849, believing that it did not have the right to make such an offer. In December 1848, he dissolved the Pru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Bonn
The University of Bonn, officially the Rhenish Friedrich Wilhelm University of Bonn (), is a public research university in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the () on 18 October 1818 by Frederick William III, as the linear successor of the () which was founded in 1777. The University of Bonn offers many undergraduate and graduate programs in a range of subjects and has 544 professors. The University of Bonn is a member of the U15 (German universities), German U15 association of major research-intensive universities in Germany and has the title of "University of Excellence" under the German Universities Excellence Initiative. Bonn has 6 Clusters of Excellence, the most of any German university; the Hausdorff Center for Mathematics, the Matter and Light for Quantum Computing cluster, Bonn Center for Dependency and Slavery Studies, PhenoRob: Research for the Future of Crop Production, the Immune Sensory System cluster, and ECONtribute: M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
