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Civil dawn is preceded by morning nautical twilight and civil dusk is followed by evening nautical twilight. Civil twilight in a small town in the Mojave Desert. Under clear weather conditions, civil twilight approximates the limit at which solar illumination suffices for the human eye to clearly distinguish terrestrial objects.
Three different concepts of "night" are referred to in the Federal Aviation Regulations in the US. These include the periods from sunset to sunrise - used for nav lights,; the end of evening civil twilight to the beginning of morning civil twilight (this is the "standard definition of night", given in FAR Section 1.1) - used for logging night flight,
Evening is the period of a day that begins at the end of daylight and overlaps with the beginning of night. [1] It generally indicates the period of time when the sun is close to the horizon and comprises the periods of civil, nautical and astronomical twilight. The exact times when evening begins and ends are subjective and depend on location ...
Civil, nautical, and astronomical twilight. [3] Dusk is the darkest part of evening twilight. The time of dusk is the moment at the very end 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]
Civil twilight refers to the part of the day when the sun is within 6 degrees below the horizon. In Utqiaġvik, civil twilight ranges from roughly 3 hours on the winter solstice to 6 hours on the ...
Twilight is the period before sunrise and after sunset in which there is natural light but no direct sunlight. [36] The morning twilight begins at dawn and ends at sunrise, while the evening twilight begins at sunset and ends at dusk. Both periods of twilight can be divided into civil twilight, nautical twilight, and astronomical twilight ...
Here, the length of daylight is defined as the period from the beginning of civil twilight in the morning to the end of civil twilight in the evening. Morning civil twilight begins before sunrise when the sun is geometrically 6 degrees below the horizon and ends when the sun rises; evening civil twilight lasts from sunset until the sun is ...
In aviation, "night" is defined as the period from "the end of evening civil twilight to the beginning of morning civil twilight". [1]: 19 [2] In EASA states and the United Kingdom, the requirements for a night rating for aeroplanes are: [1]: FCL.810 [3] theoretical instruction