American practical navigator: an epitome of navigation and nautical astronomy (1914)
Bowditch, Nathaniel, 1773-1838, Logan, George Wood, 1868-1915, United States. Navy Dept. Bureau of Equipment · Washington, Govt. Print. Off · leaf 125
earth, is ZAS;seen from C it is ZCS; the parallax is the difference of these angles, ZAS-ZCS=ASC. Parallax in altitude is, then, the angle atthe heavenly body subtended by the radiusof the earth. If the heavenly body is hi the horizon asat II, the radius, being at right angles to AH,subtends the… … FIG. 47. Let par. = parallax in altitude, ASC; Z=SAZ, the apparent zenith distance (corrected for refraction); R=AC, the radius of the earth; and D = CS, the distance of the object from the center of the earth. Then, since SAC = 180°-SAZ, the triangle ASC gives: R sin Zsin par. = —^—. If the object…
Navigation · Nautical astronomy
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