An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The time between sunset or sunrise and the moment when the Sun's center lies 6° below the horizon. It is followed or preceded by → nautical twilight. See also → astronomical twilight. In the morning, this twilight phase ends at sunrise. In the evening it begins at sunset. Civil twilight is the brightest of the three twilight phases. As the Earth's atmosphere scatters and reflects much of the Sun's rays, artificial lighting is generally not required in clear weather conditions to carry out most outdoor activities. Only the brightest stars and planets, like Venus and Jupiter, can be seen with the naked eye.

→ civil; → twilight.