The practical astronomer : comprising illustrations of light and colours, practical descriptions of all kinds of telescopes, the use of the equatorial-transit, circular, and other astronomical instruments, a particular account of the Earl of Rosse's large telescopes, and other topics connected with astronomy (1845)
Dick, Thomas, 1774-1857 · London : Seeley, Burnside, and Seeley · leaf 296
ass the rays of differentcolours were bent from theirrectilineal course with the sameequality and regularity as inreflection. Telescopes constructed with such object-glasseswere examined by the late Dr. Robison and pro-fessor Play fair. The focal distance of the object-glass of one of these did not… … 272 THE PRACTICAL ASTRONOMER. tinctness, it was manifestly superior to one of Mr.Dollond of 42 inches focal length. They hadmost distinct vision of a star, when using an erect-ing eye-piece, which made this telescope magnifymore than a 100 times ; and they found the fieldof vision as uniformly…
Astronomy · Astronomical instruments · Telescopes
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