![]() ![]() Similar to twilight, dusk is classified into three main subcategories civil, nautical, and astronomical dusk. At dusk, artificial light is required while reading outside since there is no sunlight to be scattered and illuminated. It marks the beginning of the evening when the sky is blue and bright. What Is Dusk? When Does Dusk Occur?ĭusk refers to the time commencing immediately after the evening twilight. The same phenomenon is experienced in the South Pole at opposite times of the year. After this phenomenon, the sun sinks below the horizon causing days of continuous civil twilight then subsequent days of nautical twilight followed by astronomical twilight. During the September equinox, there is no twilight at all in the North Pole due to the Polar Day and Midnight Sun. ![]() During the polar regions during the March equinox, the North Pole does not experience nautical and astronomical twilight rather, there is continuous civil twilight. The length of twilight is dependent on the latitudes where tropical and equatorial regions have shorter twilights as compare to in higher latitudes. It is the darkest twilight when the sky is dark enough for all kinds of astronomical observations. Dusk refers to the time commencing immediately after the evening twilight. The phenomenon is used by the US military to commence their twilight tactical operations.Īstronomical twilight is the time when the sun lies between 12 and 18 degrees below the earth’s horizon. ![]() Nautical twilight dates back to the ancient times when sailors used the stars to navigate the sea. During the nautical twilight, artificial light is required for outdoor activities since there is little sunlight illuminating the earth’s atmosphere. Nautical twilight occurs when the sun lies between 6 and 12 degrees below the horizon. Countries use the definition of the civil twilight to enact laws relating to hunting, aviation, and the use of headlights. It is the brightest twilight and the horizon is seen clearly without the help of artificial light. Astronomers define twilight under three distinct subcategories civil, nautical, and astronomical twilight based on the sun's elevation relative to the earth’s horizon.Ĭivil twilight occurs when the sun falls below 6 degrees on the earth’s horizon. During twilight, sunlight is scattered in the upper atmosphere and illuminating on the earth’s lower atmosphere. Twilight is the time of the day between sunrise and dawn and the time between sunset and dusk. What Is Twilight? When Does Twilight Occur? The timing of twilight and dusk can vary based on various factors such as the position of the observer in relation to latitudes, seasonal variations, and the position of the sun. Twilight and dusk refer to different occurrences relating to the movement of the sun on the solar elevation angle. ![]()
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