The geography of the heavens : and class-book of astronomy : accompanied by a celestial atlas (1860)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York : Mason Brothers · leaf 317
, soas to be taken into the human eye through the pupil, which is but one-fourth of an inchin diameter. Our vision is thus made as perfect bj art as if nature had given us abilityto enlarge the eye till the pupil was a foot in diameter. 688. Refracting telescopes may consist of a double-convexlens… … Here the parallel rays are seen to pass through the lens at A, and to be so convergedto a point as to enter the eye of the beholder at B. His eye is thus virtually enlarged tothe size of the lens at A. But it would be very difficult to direct such a telescope towardcelestial objects, or to get the…
Constellations · Stars
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