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 338
the eye-tubes, which consists oftwo distinct pieces of mahogony; the part Dbeing capable of sliding along the under side ofC, through the brass sockets EF. To the underpart of the socket F is attached a brass nut witha female screw, in which the male screw ah actsby applying the hand to the knob e,… … passes through a nut connected with anotherstrong wire, which passes through the arm D. Bymeans of the nut/this tube may be elevated ordepressed, and firmly fixed in its proper position;and by the nut d it may be brought nearer to orfurther from, the arm D. By the same apparatus, it is also…
Astronomy · Astronomical instruments · Telescopes
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