Stars and telescopes; a hand-book of popular astronomy, founded on the 9th ed. of Lynn's Celestial motions (1899)
Todd, David P. (David Peck), 1855-1939, Lynn, William Thynne, 1835-1911. Celestial motions · Boston, Little, Brown and company · leaf 416
al the objective was found so nearly satis-factory that only twenty minutes were required to ren-der it sensibly perfect. In this achromatic glass, withthe flint lens in advance of the crown, with a spaceof oin.i between them, a variation of this latter dis-tance will effectively correct the… … A MODERN CAMERA FOR STELLAR PHOTOGRAPHY( With equatorial mounting designed by Heyde) with the calculated value, which is often a markedadvantage. The effect of focal length upon the performance ofa lens is excellently shown by the wonderful photo- 358 Stars and Telescopes graphs of the Milky Way…
Astronomy
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