An introduction to astronomy : designed as a text book for the students of Yale College (1846)
Olmsted, Denison, 1791-1859, Yale College (1718-1887) · New York : Collins, Brother & Co. · leaf 81
equire to know the altitude of a celestial body when it isnot on the meridian, and its azimuth, or distance from the meridianmeasured on the horizon; and also the angular distance betweentwo points on any part of the celestial sphere. An instrumentespecially designed to measure altitudes and… … ASTRONOMICAL INSTRUMENTS. 57 compass, the direction of the meridian being determined by theneedle; but when the object, as a star, is not on the horizon, itsazimuth, it must be remembered, is the arc of the horizon fromthe meridian to a vertical circle passing through the star (Art. 27);at whatever…
Astronomy
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