# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Astro*Dictionary by Michael Erlewine

 

 

 

 

2 articles for "Twilight"

Twilight [Astro*Index]

The period of relative illumination after sunset; i.e., after the sun passes completely below the Horizon. This can last for nearly an hour, depending on the latitude, and is longer in summer than winter in northern latitudes. It is due to the Sun's light being reflected off atmospheric clouds and dust.

See also:
♦ Sunset ♦ Horizon
Twilight [DeVore]

The illumination of the Earth's atmosphere after sun set, visible until the Sun is about 18° below the horizon. Its duration depends upon the time required for the Sun to traverse this distance. At the Equator this requires about an hour at any time of year, but during Summer lasts for a much longer period. As one passes beyond 40° N. latitude, the interval is lengthened in the Summer and shortened in the Water.

See also:
♦ Sunset ♦ Horizon

 

Astro*Index Copyright © 1997 Michael Erlewine