Lessons in astronomy including uranography. A brief intoductory course without mathematics (1896)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston, London, Ginn and company · leaf 330
north or south of the celestial equa-tor at the moment of transit. The circle-reading for theequator must first be determined as a zero point; and this isdone by observing a star near the pole and getting the circle-reading as it crosses the meridian above the pole, and twelvehours later, when it… … Fig. 90. — The Meridian Circle (Schematic). 419. The Nadir Point. —To get the latitude of the observerwith this instrument (Art. 81), it is necessary also to have thenadir point as a zero ; i.e., the circle-reading which correspondsto the vertical position of the telescope. This point is foundby…
Astronomy
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