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Peter Andreas Hansen
Peter Andreas Hansen (born 8 December 1795, Tønder, Schleswig, Denmark; died 28 March 1874, Gotha, Thuringia, Germany) was a Danish-born German astronomer. Biography The son of a goldsmith, Hansen learned the trade of a watchmaker at Flensburg, and exercised it at Berlin and Tønder, 1818–1820. He had, however, long been a student of science; and Dr Dircks, a physician practising at Tønder, prevailed with his father to send him in 1820 to Copenhagen, where he won the patronage of H.C. Schumacher and attracted the personal notice of King Frederick VI. The Danish survey was then in progress, and he acted as Schumacher's assistant in work connected with it, chiefly at the new observatory of Altona, from 1821–1825. Thence he passed on to Gotha as director of the Gotha Observatory; nor could he be tempted to relinquish the post by successive invitations to replace F.G.W. Struve at Dorpat in 1829, Friedrich Wilhelm August Argelander at Helsinki in 1837, and F.W. Bessel at Kö ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tønder
Tønder (; german: Tondern ) is a town in the Region of Southern Denmark. With a population of 7,505 (as of 1 January 2022), it is the main town and the administrative seat of the Tønder Municipality. History The first mention of Tønder might have been in the mid-12th century, when the Arab geographer Muhammad al-Idrisi mentioned the landmark ''Tu(r)ndira'', which might have been a reference to either Tønder, or the nearby town of Møgeltønder. Tønder was granted port privileges by the Hanseatic League in 1243, making it Denmark's oldest privileged market town. In 1532 it was hit by severe floods, with water levels reaching 1.8 m in St Laurent's church, 5.3 m above sea level. In the 1550s, Tønder's port lost direct access to the sea due to dykes being built to the west of town at the direction of Duke Hans the Elder of Schleswig-Holstein-Haderslev, the son of Frederick I of Denmark. The town centre is dominated by houses from the late 17th and early 18th century, when th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gotha Observatory
Gotha Observatory (''Seeberg Observatory'', ''Sternwarte Gotha'' or ''Seeberg-Sternwarte'') was a German astronomical observatory located on Seeberg hill near Gotha, Thuringia, Germany. Initially the observatory was dedicated to astrometry, geodetic and meteorological observation and tracking the time. The minor planet 1346 Gotha was named after the city of Gotha in recognition of the observatory. History Planning for the observatory began in 1787 by the court astronomer Baron Franz Xaver von Zach, with the financing of Ernest II, Duke of Saxe-Gotha-Altenburg. It was based upon the Radcliffe Observatory in Oxford, England. The building was divided into five parts, with the central section holding a revolving dome. There were two wings to provide quarters for the staff. During Peter Andreas Hansen's term, the observatory was dismantled and moved to a less exposed location in Gotha. The observatory was closed in 1934. Instruments Around 1800, the observatory became an internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernest William Brown
Ernest William Brown FRS (29 November 1866 – 22 July 1938) was an English mathematician and astronomer, who spent the majority of his career working in the United States and became a naturalised American citizen in 1923. His life's work was the study of the Moon's motion (lunar theory) and the compilation of extremely accurate lunar tables. He also studied the motion of the planets and calculated the orbits of Trojan asteroids. Life and career Brown was born in Hull, England, the second of four children of William and Emma Brown (née Martin). His father was originally a farmer and later became a timber merchant. His mother and younger brother died of scarlet fever in 1870, when Brown was not quite 4 years old. He and his two sisters were then looked after by a maiden aunt, until his father remarried five years later. Education and early career Brown was educated at Totteridge Park School, Hertfordshire (now part of Dorset House School) anHull and East Riding College After ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simon Newcomb
Simon Newcomb (March 12, 1835 – July 11, 1909) was a Canadian–American astronomer, applied mathematician, and autodidactic polymath. He served as Professor of Mathematics in the United States Navy and at Johns Hopkins University. Born in Nova Scotia, at the age of 19 Newcomb left an apprenticeship to join his father in Massachusetts, where the latter was teaching. Though Newcomb had little conventional schooling, he completed a BSc at Harvard in 1858. He later made important contributions to timekeeping, as well as to other fields in applied mathematics, such as economics and statistics. Fluent in several languages, he also wrote and published several popular science books and a science fiction novel. Biography Early life Simon Newcomb was born in the town of Wallace, Nova Scotia. His parents were John Burton Newcomb and his wife Miriam Steeves. His father was an itinerant school teacher, and frequently moved in order to teach in different parts of Canada, particularly in N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Almanac
A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea. The Almanac specifies for each whole hour of the year the position on the Earth's surface (in declination and Greenwich hour angle) at which the Sun, Moon, planets, and First Point of Aries is directly overhead. The positions of 57 selected stars are specified relative to the First Point of Aries. In Great Britain, ''The Nautical Almanac'' has been published annually by HM Nautical Almanac Office, ever since the first edition was published in 1767. In the United States, a nautical almanac has been published annually by the US Naval Observatory since 1852. It was originally titled '' American Ephemeris and Nautical Almanac''. Since 1958, the USNO and HMNAO have jointly published a unified nautical almanac, ''The Astronomical Almanac'' for use by the navies of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Theory
Lunar theory attempts to account for the motions of the Moon. There are many small variations (or perturbations) in the Moon's motion, and many attempts have been made to account for them. After centuries of being problematic, lunar motion can now be modeled to a very high degree of accuracy (see section Modern developments). Lunar theory includes: * the background of general theory; including mathematical techniques used to analyze the Moon's motion and to generate formulae and algorithms for predicting its movements; and also * quantitative formulae, algorithms, and geometrical diagrams that may be used to compute the Moon's position for a given time; often by the help of tables based on the algorithms. Lunar theory has a history of over 2000 years of investigation. Its more modern developments have been used over the last three centuries for fundamental scientific and technological purposes, and are still being used in that way. Applications Applications of lunar theory have i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. Saturn's interior is most likely composed of a core of iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The outer atmosphere is g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth the mass of the Sun. Jupiter is the List of brightest natural objects in the sky, third brightest natural object in the Earth's night sky after the Moon and Venus, and it has been observed since Pre-history, prehistoric times. It was named after the Jupiter (mythology), Roman god Jupiter, the king of the gods. Jupiter is primarily composed of hydrogen, but helium constitutes one-quarter of its mass and one-tenth of its volume. It probably has a rocky core of heavier elements, but, like the other giant planets in the Solar System, it lacks a well-defined solid surface. The ongoing contraction of Jupiter's interior generates more heat than it receives from the Sun. Because of its rapid rotation, the planet' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perturbation (astronomy)
In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive body. The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body. Introduction The study of perturbations began with the first attempts to predict planetary motions in the sky. In ancient times the causes were unknown. Isaac Newton, at the time he formulated his laws of motion and of gravitation, applied them to the first analysis of perturbations, recognizing the complex difficulties of their calculation. Many of the great mathematicians since then have given attention to the various problems involved; throughout the 18th and 19th centuries there was demand for accurate tables of the position of the Moon and planets for marine navigation. The complex motions of gravitational perturbations can be broken down. The hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Königsberg
Königsberg (, ) was the historic Prussian city that is now Kaliningrad, Russia. Königsberg was founded in 1255 on the site of the ancient Old Prussian settlement ''Twangste'' by the Teutonic Knights during the Northern Crusades, and was named in honour of King Ottokar II of Bohemia. A Baltic port city, it successively became the capital of the Królewiec Voivodeship, the State of the Teutonic Order, the Duchy of Prussia and the provinces of East Prussia and Prussia. Königsberg remained the coronation city of the Prussian monarchy, though the capital was moved to Berlin in 1701. Between the thirteenth and the twentieth centuries, the inhabitants spoke predominantly German, but the multicultural city also had a profound influence upon the Lithuanian and Polish cultures. The city was a publishing center of Lutheran literature, including the first Polish translation of the New Testament, printed in the city in 1551, the first book in Lithuanian and the first Lutheran catechism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Wilhelm Bessel
Friedrich Wilhelm Bessel (; 22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist, and geodesist. He was the first astronomer who determined reliable values for the distance from the sun to another star by the method of parallax. A special type of mathematical functions were named Bessel functions after Bessel's death, though they had originally been discovered by Daniel Bernoulli and then generalised by Bessel. Life and family Bessel was born in Minden, Westphalia, then capital of the Prussian administrative region Minden-Ravensberg, as second son of a civil servant into a large family. At the age of 14 Bessel was apprenticed to the import-export concern Kulenkamp at Bremen. The business's reliance on cargo ships led him to turn his mathematical skills to problems in navigation. This in turn led to an interest in astronomy as a way of determining longitude. Bessel came to the attention of a major figure of German astronomy at the time, Heinrich Wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helsinki
Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and towns in Finland, most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of Uusimaa in southern Finland, and has a population of . The Helsinki urban area, city's urban area has a population of , making it by far the List of urban areas in Finland by population, most populous urban area in Finland as well as the country's most important center for politics, education, finance, culture, and research; while Tampere in the Pirkanmaa region, located to the north from Helsinki, is the second largest urban area in Finland. Helsinki is located north of Tallinn, Estonia, east of Stockholm, Sweden, and west of Saint Petersburg, Russia. It has History of Helsinki, close historical ties with these three cities. Together with the cities of Espoo, Vantaa, and Kauniainen (and surrounding commuter towns, including the eastern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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