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 212
V, and whichpass through it, are converged to their respectivefoci, on the opposite wall of the chamber HG oron a white moveable screen placed in the focus ofthe lens, where they all combine to paint a livelyand beautiful picture of the range of objectsdirectly opposite, and on each side, so far as… … hand, the lens may be placed in a short tube madeof pasteboard or any other material, and fixed inthe hole made in the window shutter. The onlyimperfection attending this method is, that thelens can exhibit those objects only which liedirectly opposite the window. Some may be disposed to consider…
Astronomy · Astronomical instruments · Telescopes
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