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 336
tube. The student should fully understand the difference between the two kinds of tele-boopes, viz.: refractors and reflectors. In one respect they are alike, as they both con-verge the rays of light to a focus; but they do it by widely differeLt processes, as thefollowing pages will show. 706.… … In this cut, the light A is seen passing from the object on the right, and falling upon(he concave surface of the reflector at B, from which it is reflected back to a focus, andenters the eye of the observer at C. This telescope has no eye-piece. 708. The focal distance of a concave reflector is…
Constellations · Stars
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