Newcomb, Simon, 1835-1909, Holden, Edward Singleton, 1846-1914, joint author · New York, H. Holt and Company · leaf 110
on 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 angle 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. 92 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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