Celestial Navigation · Twilight — Times in the Almanac
The Nautical Almanac tabulates the times of nautical and civil twilight to help the navigator:
- APlan when to be on deck to observe stars and planets against a visible horizon✓ Correct
- BSet the ship's clocks to local time
- CFind the equation of time
- DDetermine the tidal range
Explanation
Twilight times tell the navigator when the horizon and the brighter bodies will both be visible — the window for star and planet sights. The Almanac gives civil and nautical twilight (and sunrise/sunset, moonrise/moonset) by latitude and date for planning the round of sights.
Authority: Nautical Almanac, twilight tables
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