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Twilight is the time between darkness and sunrise in the morning, and sunset and complete darkness in the evening, when there is light outside, but the Sun is below the horizon. There are 3 types of twilight: civil, nautical, and astronomical. Dubai skyline in twilight.
Ending of evening nautical twilight. Is defined as the instant in the evening, when the centre of the Sun is at a depression angle of twelve degrees (12Â°) below an ideal horizon. At this time in the absence of moonlight, artificial lighting or adverse atmospheric conditions, it is dark for normal practical purposes.