American practical navigator: an epitome of navigation and nautical astronomy (1914)
Bowditch, Nathaniel, 1773-1838, United States. Navy Dept. Bureau of Equipment, Logan, George Wood, 1868-1915 · Washington, Govt. Print. Off. · leaf 122
o the curved path at the eye of theobserver, and the difference of the direction of the ray before entering the atmosphereand this last direction constitutes the refraction. 297. To illustrate this, consider the earths atmosphere as shown in figure 44;let SB be a ray from a star S, entering the… … 116 CORRECTION OF OBSERVED ALTITUDES. the vertical line of the observer, by a law of optics the vertical plane of the observerwhich contains the tangent AS must also contain the whole curve BA and the incidentray BS. Hence refraction increases the apparent altitude of a star without affectingits…
Navigation · Nautical astronomy
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