nautical twilight
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nautical twilight
See twilight.Collins Dictionary of Astronomy © Market House Books Ltd, 2006
nautical twilight
[′nȯd·ə·kəl ′twī‚līt] (astronomy)
The interval of incomplete darkness between sunrise or sunset and the time at which the center of the sun's disk is 12° below the celestial horizon.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
nautical twilight
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