Dusk occurs at the darkest stage of
twilight, or at the very end of astronomical twilight after
sunset
Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation. As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring ...
and just before nightfall.
[''The Random House College Dictionary'', "dusk".] At predusk, during early to intermediate stages of twilight, enough
light in the sky
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terah ...
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
The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether i ...
), such lighting is required to read outside.
The term ''dusk'' usually refers to astronomical dusk, or the darkest part of twilight before night begins.
Technical definitions
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''. However, technically, the three stages of dusk are as follows:
*At civil dusk, the center of the Sun's disc goes 6° below the horizon in the evening. It marks the end 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 to become visible to the naked eye. The sky has many colors at this time, such as orange and red. Beyond this point artificial light may be needed to carry out outdoor activities, depending on atmospheric conditions and location.
*At nautical dusk, the Sun apparently moves to 12° below the horizon in the evening. It marks the end of nautical twilight, which begins at civil dusk. At this time, objects are less distinguishable, and stars and planets appear to brighten.
*At astronomical dusk, the Sun's position is 18° below the horizon in the evening. It marks the end 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.
Media
Dusk can be used to 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)
''Dusk'' (stylized in all caps) is a 2018 retro-styled first-person shooter created by American developer David Szymanski and published by New Blood Interactive for Microsoft Windows, macOS, Linux, and Nintendo Switch. The game is produced by ...
by New Blood Interactive whose setting is in a similar lighting as the actual time of day.
Gallery
File:Seattle 3.jpg, Seattle, Washington during Nautical twilight
File:PortoCovo February 2008-4.jpg, Civil twilight in Porto Covo
Porto Covo is one of the two civil parishes in the municipality of Sines, located along the western Alentejo coast of Portugal, about south of Lisbon. The population in 2011 was 1,038,[Magere Brug
The Magere Brug (English: Skinny Bridge) is a bridge over the river Amstel in Amsterdam, Netherlands. It connects the banks of the river at Kerkstraat, between the Keizersgracht and Prinsengracht.
The central section of the Magere Brug is a basc ...]
, Amsterdam – astronomical twilight
File:IbirapueraDusk.jpg, View from Ibirapuera Park, São Paulo, Brazil, at civil twilight
File:Deep blue sky in twilight with trees and garage.JPG, Trees' silhouettes against dusk sky
File:Albi at dusk - 2014-02-22.jpg, Civil twilight in Albi, France
File:Amoudi Bay at Dusk.jpg, Amoudi Bay
Amoudi Bay is a bay on the Greek Island of Santorini
Santorini ( el, Σαντορίνη, ), officially Thira (Greek: Θήρα ) and classical Greek Thera (English pronunciation ), is an island in the southern Aegean Sea, about 200 km (12 ...
, Santorini
Santorini ( el, Σαντορίνη, ), officially Thira (Greek: Θήρα ) and classical Greek Thera (English pronunciation ), is an island in the southern Aegean Sea, about 200 km (120 mi) southeast from the Greek mainland. It is the ...
, at dusk
File:Dusk at Hakaniemenranta in Siltasaari, Helsinki, Finland, 2021 July.jpg, Dusk in Siltasaari
Siltasaari (Finnish), or Broholmen (Swedish), is a central neighborhood of Helsinki, Finland. Most of its area is unofficially known also as Hakaniemi
Hakaniemi (; sv, Hagnäs) is an unofficial district of Helsinki, the Finnish capital. It cove ...
, Helsinki, Finland
File:VancouverConventionCenter.JPG, Nautical twilight in Vancouver, British Columbia, Canada
See also
*
Dawn
*
Sunrise
*
Sunset
Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation. As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring ...
*
Twilight
References
{{Parts of a day
Earth phenomena
Parts of a day
Night