Twilight Calculator
| Astronomical Dawn (-18°) | 04:21 |
| Nautical Dawn (-12°) | 04:59 |
| Civil Dawn (-6°) | 05:34 |
| Sunrise | 06:03 |
| Sunset | 19:44 |
| Civil Dusk (-6°) | 20:13 |
| Nautical Dusk (-12°) | 20:48 |
| Astronomical Dusk (-18°) | 21:26 |
Three Kinds of Twilight
Twilight is measured by how far the sun is below the horizon. There are three standard definitions, each useful in different contexts:
Civil twilight (sun between 0° and -6°): the horizon is clearly visible and the brightest stars are appearing. Outdoor activity is still comfortable without artificial light.
Nautical twilight (sun between -6° and -12°): the horizon is still distinguishable at sea, which is why sailors use it for star-sightings.
Astronomical twilight (sun between -12° and -18°): past this the sky is fully dark for observing faint astronomical objects.
At high latitudes one or more twilights may be absent at certain times of year. If the sun never reaches -18° (e.g., London in summer), the astronomical row reads "does not occur today".