Newcomb, Simon, 1835-1909, Holden, Edward Singleton, 1846-1914, joint author · New York : H. Holt and company · leaf 112
n of the telescope (usually the plane of the meridian), and itcan be independently rotated on the axis of the divided circle, andset by means of it to any a^gle with the optical axis of the telescope.The circle is divided from zero (0°) at its lowest point to 90° ineach direction, and is firmly… … Fig. 39.—the zenith telescope. 9a ASTRONOMY. and then rotating the telescope and the whole system about thehorizontal axis until the bubble of the level is in the centre of thelevel-tube, the axis of the telescopes will be directed to the zenithdistance a. The filar micrometer is so adjusted that a…
Astronomy
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