Navigation
Sunrise, sunset and twilight
Times of sunrise, sunset, the sun's meridian passage and civil and nautical twilight for any position and date, in UTC or ship's time.
UTC offset: 0 for UTC, 2 for UTC+2
Fill in the fields to see the result.
A dash means the event doesn't happen that day (midnight sun, polar night, or no full darkness).
How it works
Sunrise and sunset are when the sun's upper limb touches the horizon: its centre 0.833° below it (refraction and semi-diameter). Civil twilight runs until the centre is 6° below (bright stars and the horizon visible: star sights), nautical twilight until 12° (the horizon fades).
The hour angle at that altitude, cos H = (sin h − sin φ sin δ) / (cos φ cos δ), is added to or taken from the meridian passage (12:00 − longitude/15 − equation of time). Times are within a minute or two of the almanac; height of eye and unusual refraction aren't included.
For training and cross-checking. Not a substitute for approved navigation equipment, nautical publications and the ship’s own procedures. Calculations run in your browser and nothing you type is stored; a PDF you download is made on our server and not kept.
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