Twilight
From Wikipedia, a free encyclopedia written in simple English for easy reading.
When people talk about twilight they either mean dawn (in the morning) or dusk (in the evening).
In the morning, dawn is when it is not dark any more, and the light of the sun is just starting to appear. In the evening, it is the other way around. The phenomenon is called dusk. The sun has disappeared, and darkness is setting in. Light fades away.
The following has been defined. All definitons in this example are for the morning. For the evening, simply switch more than and less than:
- Civil twilight is when the sun is less than 6° below the horizon. It ends at sunrise.
- Nautical twilight' is when the sun is between 6° and 12° below the horizon.
- Astronomical twilight is when the sun is between 12° and 18° below the horizon.
For all these definitions, the horizon is at the sea, that is flat.
[edit] External links
Wikimedia Commons has media related to:
Twilight
- Definition of Twilight, US Naval Observatory
- Twilight time calculator
