The geography of the heavens and classbook of astronomy; (1863)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868, Whitall, Henry, 1819-1887? Celestial planisphere. [from old catalog] · New York, Mason brothers; Boston, Mason & Hamlin; [etc., etc.] · leaf 323
2.6 E. A COMET SEEKER. 701. A Comet Seeker is a re-fracting telescope with a largeaperture and short focal distance.As comets cannot be found bytheir right ascension and declina-tion, but often have to besearched up, by sweeping aroundthe heavens with a telescope, be-fore they become visible to… … REFLECTIXG TELESCOPES. 702. The Reflecting Telescope is one in which the light is con-verged to a focus by means of a concave metallic reflector orspeculum. Like the Refractors, they may be constructed withvery little mounting ; though for convenience in use, it is neces-sary to place the reflector…
Constellations · Stars
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