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 ?
Dotted lines indicate start of nautical twilight (blue), start of civil twilight (green), sunrise (red), sunset (red), end of civil twilight (green) and end of nautical twilight (blue) from left to right (https://www.ivb.cz/wp-content/uploads/FZ-vol.-68-2-2019-He-et-al.-Fig._S1-1.jpg).
Civil twilight occurs from when the sun is 6[degrees] below the horizon until sunrise.
The way I see it, civil twilight is a signal that registers.
with no electrical, you will need to be on the ground before the end of civil twilight." I may be mistaken but without lights, FAR 91.209 mandates you be finished by sunset.
The last glimmer of civil twilight will last till 19h16, and the celestial object will in its turn hide itself below the horizon nine minutes later.
04 "Sustainable design" may be a tired buzzword, but VITAMIN GREEN (Phaidon) highlights buildings and products--the Oru kayak by San Francisco-based collective Civil Twilight, for example that suggest green design, at its best, can live up to the hype.
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.
Taking its cue (and deriving its name) from l'heure bleue, that fleeting moment of atmospheric ambivalence at dawn and dusk when daylight has not yet begun (or has just finished) drawing a world of legibility and clear distinction, Nathaniel Robinson's New York solo debut, "Civil Twilight," operated within a territory of formal, conceptual, and material indeterminacy.
VISUAL CAPABILITIES, AMBIENT ILLUMINATION, AND CIVIL TWILIGHT
Two photoperiods were provided: natural day length, where the longest day is about 16.9 h including civil twilight or 15.7 h exclusive of twilight; and natural day length extended to 20 h with incandescent lamps (ILD).
The time, in local laws, most often correlates with civil twilight or sunrise and sunset.
The beginning of local civil twilight ([CT.sub.B] - civil twilight is the instant when the true geocentric zenith distance of the solar disk is 96[degrees], i.e.