Dusk

Landers, California at astronomical dusk (20-second exposure)

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

  1. ^ The Random House College Dictionary, "dusk".
  2. ^ "Rise, Set, and Twilight Definitions". USNO. Archived from the original on 2019-09-27. Retrieved 2015-06-19.