The geography of the heavens, and class-book of astronomy: accompanied by a celestial atlas (1873)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868, ed, Whitall, Henry, 1819-1887? Celestial planisphere · New York, Sheldon & company · leaf 337
s 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. 710. The Newtonian Reflector is so called after Sir IsaacNewton, its inventor.… … 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. 111. 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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