Clark , Alvan Graham

Clark , Alvan Graham
(1832–1897) American astronomer and instrument-maker
Clark, the son of the instrument-maker Alvan Clark, was born at Fall River, Massachusetts. He started life as a portrait painter but soon joined his father's firm and became a lens grinder, preparing the mirrors and lenses for some of the best telescopes of the late 19th century. In 1861 he had made a lens for Edward Barnard at the University of Mississippi. Testing it before parting with it he looked through it at Sirius and to his surprise observed a faint image near the star. It was, in fact, Sirius B, the famous companion predicted by Friedrich Bessel in 1844. Clark made many more observations, and discovered 16 double stars.
The Clark firm provided Simon Newcomb, head of the US Naval Observatory, with a 26-inch (66-cm) refractor. It was with this that the very small satellites of Mars, Phobos, and Deimos were detected by Asaph Hall in 1877. In 1888 Clark built the 36-inch (91-cm) refractor for the Lick Observatory and his final achievement, just before his death, was to install his 40-inch (101-cm) refractor in the Yerkes Observatory. A practical limit is reached in using lenses larger than this and after Clark's death astronomers put their faith in mirrors rather than lenses. For this reason the Yerkes 40-inch and the Lick 36-inch are still the largest and the second largest refractors in the world.

Scientists. . 2011.

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  • Alvan Graham Clark — Infobox Scientist name = Alvan Graham Clark image width = 260px caption = Alvan Clark and his assistant Carl Ludin (right) alongside of the 40 inch lens, 1896. birth date = birth date|1832|7|10|mf=y birth place = Fall River, Massachusetts death… …   Wikipedia

  • Alvan Graham Clark — Pour les articles homonymes, voir Clark. Alvan Graham Clark (10 juillet 1832 – 9 juin 1897), né à Fall River dans le Massachusetts, était un astronome et un fabricant d optique américain. Il était le fils d Alvan Clark. En 1862, alors qu il… …   Wikipédia en Français

  • Alvan Graham Clark — Saltar a navegación, búsqueda Alvan Graham Clark y su asistente (a la derecha) Alvan Graham Clark (1832 1897). Óptico norteamericano, constructor de grandes objetivos para telescopios refractores. Inició su aprendizaje en el fundido, talla y… …   Wikipedia Español

  • Alvan Graham Clark — (links). Alvan Graham Clark (* 10. Juli 1832 in Fall River, Massachusetts; † 9. Juni 1897 in Cambridge, Massachusetts) war ein US amerikanischer Astronom und Teleskopbauer. Er war der Sohn des Teleskopbauers Alvan Cla …   Deutsch Wikipedia

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  • Alvan Clark & Sons — was an American maker of optics that became famous for crafting lenses for some of the largest refracting telescopes of the nineteenth and early twentieth centuries. Founded in 1846 in Cambridgeport, Massachusetts by Alvan Clark (1804 ndash;1887 …   Wikipedia

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  • Clark (Familienname) — Clark ist ein englischer Familienname. Herkunft und Bedeutung Der Name entspricht dem neuenglischen clerk und damit in etwa dem deutschen Namen Schreiber. Varianten Clarke, Clerke Bekannte Namensträger Inhaltsverzeichnis A B C D …   Deutsch Wikipedia

  • Clark — Clark, 1) Alvan, Mechaniker, geb. 8. März 1804 zu Ashfield in Massachusetts, gest. 19. Aug. 1887 in Cambridgeport. Anfangs Porträtmaler und Graveur, begann er 1836 in Cambridgeport bei Boston Fernrohre zu bauen und lieferte bald größere, deren… …   Meyers Großes Konversations-Lexikon

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