The royal Observatory of Greenwich (in English Royal Observatory, Greenwich shortened by the Initials ROG; in the past Royal Greenwich Observatory or RGO) is a astronomical Observatoire British located in the park of Greenwich, in the Banlieue is of London, in overhang of the the Thames.
Foundation
It was created the June 22nd 1675 on order of the king Charles II of England, which at the same time created for its director the station of royal Astronomer ( Astronomer Royal ). This last was “to apply with the greatest care and greatest diligence to correct the tables indicating the movements of the sky and the place of fixed stars, in order to determine best the Longitude S and to improve the art of navigation. ”In the beginning, the part which constituted the observatory was called Flamsteed House name of its first director John Flamsteed, and was conceived by the Architecte Sir Christopher Wren. It was the first time in England which a building was specifically built with an aim of accommodating an installation of scientific research. It sheltered not only the scientific instruments which was to be used by Flamsteed for its work on the tables of stars, but, thereafter, one assigned some additional tasks to him, like the Mesure of time and later the service of the nautical Almanac of his Majesty ( Her Majesty' S Nautical Almanac Office ).
The British astronomers made use a long time of the Royal Observatory to found their measurements: four Méridien S distinct were successively traced inside the building. The starting point of the Longitude S, the prime meridian ( Premium Meridian ), was given in 1851 and adopted at the time of an International Conference in October 1884; at the origin it passed through the observatory. A long time it was marked by a band in Cuivre in the court, replaced now by another in Stainless steel. Finally, since the December 16th 1999, it is marked by powerful a green Laser which at night shines towards north through London.
At the time where the observatory of Greenwich was in activity, the geographical Coordonnées referred to a Sphéroïde oblate (i.e. flattened with the pole S) whose surface corresponded as much as possible at the local average level of the sea. In the whole world, it was necessary to use several data, which all used different spheroids, because the mean level of the sea varies of more than 100 meters according to the places. The modern geodetic frames of reference, like the geodetic System of the world and the terrestrial Framework of reference international, make use of a spheroid oblate. Because of the passage of several spheroids to a world spheroid, all the geographical coordinates changed, sometimes several hundreds of meters. The principal Meridian line on which are based the modern frames of reference passes to approximately 100 meters to the east of the astronomical meridian line of Greenwich which represented the copper band.
The Greenwich mean time ( Greenwich Mean Time ) was based initially on the observations of time made in Greenwich, before it was replaced by the universal Time coordinated. Installed by the royal astronomer John Lays in 1833, a swell indicating time drops each day to mark 13 hours exactly.
Today, the building shelters a museum of instruments intended for the Astronomie and the Navigation, in particular the famous Chronomètres H1 in H4 of John Harrison. In February 2005, one started to refit the Observatory according to a program which will cost on 15 million books]; one will have new then [[planetarium]], additional galleries of exposure and educational equipment. == Voir also == === external Bond === * {{Fr}} [http://www.nmm.ac.uk/server.php?show=nav.005008000 Official site] {{Multi stringcourse|Gate astronomy|gate geography}} [[Category: Astronomical observatory in the United Kingdom|Greenwich]] [[Category: Greenwich (London district)]] [[Category: London museum]] [[Category: Measure time]] [[Cs: Královská greenvichská observatoř]] [[cy: Yr Arsyllfa Frenhinol, Greenwich]] [[of: Royal Greenwich Observatory]] [[in: Royal Observatory, Greenwich]] [[be: Observatorio of Greenwich]] [[He: מצפההכוכביםהמלכותישלגריניץ ']] [[it: Osservatorio di Greenwich]] [[ja: グリニッジ天文台]] [[KB: 그리니치천문대]] [[nl: Koninklijk Greenwich Observatorium]] [[pl: Królewskie Obserwatorium Astronomiczne W Greenwich]] [[Pt: Observatório of Greenwich]] [[ro: Observatorul Treat DIN Greenwich]] [[tr: Greenwich Gözlemevi]] [[zh: 格林尼治天文台
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