For other uses, see Dusk (disambiguation).
See also: Sunset
Astronomical Dusk

Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight just before night.[1] Pre-dusk, during early to intermediate stages of twilight, there may be enough light in the sky under clear-sky conditions to read outdoors without artificial illumination, but at the end of civil twilight, when the earth rotates to a point at which the center of the sun is at 6° below the local horizon, artificial illumination is required to read outside.[2] "Dusk" is actually short for Astronomical Dusk, or the darkest part of twilight before night begins.

Technical definitions

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 total darkness or night, or may be thought of as the darkest part of twilight.[4]

Seattle, Washington during Nautical twilight

See also


  1. The Random House College Dictionary, "dusk".
  2. 1 2 U.S. Naval Observatory. Rise, Set, and Twilight Definitions.
  3. Van Flandern, T.; K. Pulkkinen (1980). "Low precision formulae for planetary positions". Astrophysical Journal Supplement Series. 31 (3). Bibcode:1979ApJS...41..391V. doi:10.1086/190623.
  4. "Full definition of Dusk".
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