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Édouard Stephan
Édouard Jean-Marie Stephan (31 August 1837 – 31 December 1923) was a French astronomer. His surname is sometimes spelled Stéphan in some literature, but this is apparently erroneous. He was born in Sainte Pezenne (today one of the districts of the town of Niort) and attended the Ecole Normale Superieure, and graduated at the top of his class in 1862. He was the director of the Marseille Observatory from 1864 to 1907 (until 1872 he was subordinate to Urbain le Verrier). In the early part of his career there, he had limited opportunities to do observations because he was preoccupied with improving the observatory. He discovered the asteroid 89 Julia in 1866. In 1867 he used the new telescope to observe a transit of Mercury. Between 1870 and 1875, Stephan systematically studied nebulae, precisely recording their positions and discovering many new ones. His goal was to enable the exact measurement of stellar proper motions by creating a reference system of fixed objects. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Édouard Jean-Marie Stephan
Édouard is both a French given name and a surname, equivalent to Edward in English. Notable people with the name include: * Édouard Balladur (born 1929), French politician * Édouard Boubat (1923–1999), French photographer * Édouard Colonne (1838–1910), French conductor * Édouard Daladier (1884–1970), French prime minister at the start of World War II * Edouard Drumont (1844–1917), French anti-semitic journalist * Édouard Dujardin (1861–1949), French writer * Édouard Gagnon (1918–2007), French Canadian cardinal * Édouard Herriot (1872–1957), French prime minister, three times, and mayor of Lyon from 1905 to 1957 * Edouard F. Henriques, Make-up artist * Édouard Lalo (1823–1892), French composer * Édouard Lockroy (1838–1913), French politician * Édouard Louis (born 1992), French Writer * Édouard Lucas (1842–1891), French mathematician * Édouard Mathé (1886–1934), French silent film actor * Édouard Manet (1832–1883), French impressionist painter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcsecond
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol , is of an arcminute, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcsecond (mas) and microarcsecond (μas), for instance, are commonly used in astron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
91 Aegina
Aegina (from Latin ''Aegīna'', ''Aegīnēta''), minor planet designation 91 Aegina, is a large main-belt asteroid. It was discovered by a French astronomer Édouard Jean-Marie Stephan on 4 November 1866. It was his second and final asteroid discovery. The first was 89 Julia. The asteroid's name comes from Aegina, a Greek mythological figure associated with the island of the same name. This body is orbiting the Sun with a period of 4.17 years and an eccentricity of 0.105. The orbit of this object brings it to within of the dwarf planet Ceres, and the resulting gravitational interaction has been used to produce mass estimates of the latter. The cross-section size of the asteroid is 110 km and it has a rotation period of six hours. The surface coloring of 91 Aegina is very dark and this C-type asteroid has probably a primitive carbonaceous composition. Observation of absorption bands at wavelength In physics, the wavelength is the spatial period of a periodic wave—t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
