Dusk
Template:Short description Template:Distinguish {{#invoke:other uses|otheruses}} Template:More citations needed
Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.<ref name=RH>The Random House College Dictionary, "dusk".</ref> 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.<ref name="USNOTwilightDefs">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The term dusk usually refers to astronomical dusk, or the darkest part of twilight before night begins.
Technical definitionsEdit
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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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 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.<ref name="USNOTwilightDefs"/><ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
GalleryEdit
- Scots pine at dusk, Ridley Plain, New Forest - geograph.org.uk - 296737.jpg
Scots pine at early dusk in New Forest, England
- Dusk at the shore, Silverdale - geograph.org.uk - 5042036.jpg
Dusk at the shore
- Eastwards at dusk from Dalvanie - geograph.org.uk - 3406039.jpg
Looking eastwards at dusk
- Sandakan at dusk (10498416104).jpg
Sandakan, Malaysia at dusk
- Beached boats on the Fleet at dusk - geograph.org.uk - 2537423.jpg
Beached boats at dusk
- Jardim Botânico, Curitiba (20240301 185956).jpg
Curitiba at dusk, Brazil
- Singapore Marina Bay Dusk 2018-02-27.jpg
Nautical dusk in Marina Bay, Singapore
- Dusk-A330.JPG
Astronomical twilight as seen from a plane window