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 287
when the telescopeis directed nearly to the object intended to beviewed. This socket may be set perpendicular tothe horizon, or to any other required angle ; andthe quantity of the angle is ascertained by thedivided arc, and the instrument made fast in thatposition by the screw e. If this socket be… … clination of the pole of the earth, the telescopewhen turned in this socket, will have an equatorialmotion, so that celestial objects may be alwayskept in view, when this equatorial motion is per-formed. The two handles at k are connected withrack-work, intended to move the telescope in anyrequired…
Astronomy · Astronomical instruments · Telescopes
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