nimtâb-e axtaršenâsik, ~ axtarsnâxti
Fr.: crépuscule astronomique
The time between sunset or sunrise and the moment when the Sun's center lies 18° below the horizon. → civil twilight.
Fr.: crépuscule civil
The time between sunset or sunrise and the moment when the Sun's center lies 6° below the horizon. → astronomical twilight.
Fr.: crépuscule nautique
The period before sunrise and after sunset when the center of the Sun's disk is between 6° and 12° below the horizon.
The diffused light from the sky when the Sun is below the → horizon, either from daybreak to → sunrise or, more commonly, from → sunset to nightfall. There are three types of twilight: → astronomical twilight, → civil twilight, and → nautical twilight. They are divided on the basis of the → solar depression angle.
M.E., cognate with Du. tweelicht, Ger. zwielicht, from twi- a combining form meaning "two, twice," but it appears to refer to "half" light, rather than the fact that twilight occurs twice a day + → light.