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 325
supposed to be off on the right, in the direction towardswhich the instrument is pointed. It is called a Gregorian telescope, after Mr. JamesGregory, who first suggested the construction of reflecting telescopes. 705. The Newtonian Reflector is so called after Sir IsaacNewton, its inventor. Instead… … The light from the speculum is here shown falling upon the inclined mirror in the cen-ter, and reflected out to the eye of the observer. 706. The Cassegranian Reflector is so called from M. Casse-grain, its inventor. It resembles the Gregorian, except that thespeculum placed in the focus of the…
Constellations · Stars
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