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 62
me cold weather, this shortening of the suns vertical diameter sometimesexceeds this amount. TWIUOHT. 37 TWILIGHT. 96. Twilight also is another phenomenon depending upon theagency of the earths atmosphere. It is due partly to refractionand partly to reflexion, but mostly the latter. While the sunis… … of the spectator at A, and let SS be a ray of light from the sunwhen it is two or three degrees below the horizon. Then tothe observer at A, the segment of the atmosphere ABS would beilluminated. To a spectator at C, whose horizon was CD, thesmall segment SDx would be the twilight; while, at E, the…
Astronomy
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