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 318
easily placed in the focus, and theobjeet-glass directed toward any desired object. 691. The object-glass of a telescope is usually protected, whennot in use, by a brass cap that shuts over the end of the instru-ment ; and the eye-pieces, of which there are several, of differ- ed. QalQsan… … ent magnifying powers,are so fixed as to screwinto a small movable tubein the lower end of theinstrument, so as toadjustthem respectively, to thefocus, and to the eyes ofdifferent observers. Suchtelescopes usually repre-sent objects in an invert-ed position. The adjoining cut represents thesimplest…
Constellations · Stars
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