civil twilight


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civil twilight

See twilight.

civil twilight

[¦si·vəl ¦twī‚līt]
(astronomy)
The interval of incomplete darkness between sunrise (or sunset) and the time when the center of the sun's disk is 6° below the horizon.

civil twilight

A period before sunrise or after sunset, commencing when the sun's center is between 0° and 6° below the horizon. This corresponds to a degree of illumination at which everyday operations begin or cease to be possible without artificial light.
References in periodicals archive ?
In Wind-up's eleven years, the company has discovered and built the careers of Creed, Evanescence, Seether, Finger Eleven, and 12 Stones, has achieved cumulative sales exceeding 50 million albums and features such upcoming stars as Thriving Ivory, Civil Twilight, Company of Thieves, Endless Hallway, Stars of Track and Field, Tickle Me Pink and others.
Nautical Twilight is from the end of civil twilight to the time that the horizon is no longer visible, usually when the Sun is 12[degrees] below the horizon, or 48 minutes after sunset.
First, there was at least about one hour of good visibility (sundown that day was at 1917 and end of civil twilight at 1945; plus, there would be some visibility during the nautical twilight) remaining after 1855 that would allow the enemy aircraft to operate against the Allied ships.
The daytime interval, 0400-1959 hrs PST, was 960 min in length and began, depending upon calendar date, an average of 24 min before the start of morning civil twilight (range = 13-45 min).
twilight Civil twilight is the period from sunset to the time that the Sun is 6[degrees] below the horizon.
At the start of the period Venus is 4[degrees] high at the end of civil twilight whilst by the end of the period, as the angle of the ecliptic increases, the planet is 11[degrees] high in the same twilight conditions.