Newcomb, Simon, 1835-1909, Holden, Edward Singleton, 1846-1914, joint author · New York : H. Holt and company · leaf 110
ut on the celestial sphere the apparent diiimal pathwhich this star will appear to follow from rising to set-ting. In such telescopes a driving-clock is so arrangedthat it can turn the telescope round the polar axis at thesame rate at which the earth itself turns about its own axisof rotation, but… … Fig. 38.—measueembnt of position-angle. Every equatorial telescope intended for making exact measureshas a Jfllar micrometer, which is precisely the same in principle asthe reading microscope in Fig. 3, page 86, except that its two wiresare parallel. A figure of this instrument is given in Fig. 3,…
Astronomy
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