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 521
ar on their inside, and firmlyunited at their extreme borders by a number ofshort braces or bars which stand perpendicularbetween them, and which keep them at such adistance as to admit the achromatic telescope TT.This double circle is supported by 16 conical bars,firmly united along with the… … of the micrometer microscopes mm, which read oftthe angle on opposite sides of each circle. Thecross wires in each microscope may be moved overthe limb till they coincide with the nearest divi-sion of the limb, by means of the micrometerscrews cc9 and the space moved through is ascer-tained by the…
Astronomy · Astronomical instruments · Telescopes
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