Dusk

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Dusk occurs at the darkest stage of twilight, or at the very over of astronomical twilight after sunset and just before nightfall.^[1] At predusk, during early vĩ đại intermediate stages of twilight, enough light in the sky under clear conditions may occur vĩ đại read outdoors without artificial illumination; however, at the over of civil twilight (when Earth rotates vĩ đại a point at which the center of the Sun's disk is 6° below the local horizon), such lighting is required vĩ đại read outside.^[2] The term dusk usually refers vĩ đại astronomical dusk, or the darkest part of twilight before night begins.

Technical definitions[edit]

The time of dusk is the moment at the very over of astronomical twilight, just before the minimum brightness of the night sky sets in, or may be thought of as the darkest part of evening twilight.^[4] However, technically, the three stages of dusk are as follows:

Astronomical twilight as seen from a plane window

At civil dusk, the center of the Sun's disc goes 6° below the horizon in the evening. It marks the over of civil twilight, which begins at sunset. At this time objects are still distinguishable and depending on weather conditions some stars and planets may start vĩ đại become visible vĩ đại the naked eye. The sky has many colors at this time, such as orange and red. Beyond this point artificial light may be needed vĩ đại carry out outdoor activities, depending on atmospheric conditions and location.
At nautical dusk, the Sun moves vĩ đại 12° below the horizon in the evening. It marks the over of nautical twilight, which begins at civil dusk. At this time, objects are less distinguishable, and stars and planets appear vĩ đại brighten.
At astronomical dusk, the Sun's position is 18° below the horizon in the evening. It marks the over of astronomical twilight, which begins at nautical dusk. After this time the Sun no longer illuminates the sky, and thus no longer interferes with astronomical observations.^[2]^[5]

Media[edit]

Dusk can be used vĩ đại create an ominous tone and has been used as a title for many projects. One instance of this is the 2018 first person shooter Dusk (video game) by New Blood Interactive whose setting is in a similar lighting as the actual time of day.