A star trail is a type of photograph that uses long exposure times to capture diurnal circles, the apparent motion of stars in the night sky due to Earth's rotation.

Polaris Star Trails
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A star trail is a type of photograph that uses long exposure times to capture diurnal circles, the apparent motion of stars in the night sky due to Earth's rotation. A star-trail photograph shows individual stars as streaks across the image, with longer exposures yielding longer arcs. The term is used for similar photos captured elsewhere, such as on board the International Space Station and on Mars.

[Source: Wikipedia, https://en.wikipedia.org/wiki/Star_trail]

Polaris Star Trails at Kejimkujik National Park and Historic Site
Exposureabout 400 frames@ 20 sec
ISO3200
CameraNikon D800 [7360 x 4912]
OpticsNikkor 24-70 mm lens
LocationSky Circle, Kejimkujik National Park and National Historic Site, Nova Scotia.
Date2013-10-06
ProcessingProcessed in StarStax and Lightroom.