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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.
Night or nighttime (sp. night-time or night time) is the period of time between the sunset and the sunrise when the Sun is below the horizon. Complete darkness or astronomical night is the period of time between astronomical dusk and astronomical dawn when the sun is between 18 and 90 degrees below the horizon and the sky is totally dark.