Editing Circumpolar star (section)

{{short description|Star that never sets due to its apparent proximity to a celestial pole}}
{{More citations needed|date=May 2018}}
[[File:Circumpolar AZ81.jpg|thumb|Circumpolar [[star trail]]s in a [[long-exposure photo]] of several hours. The stars near the celestial pole leave shorter trails with the long exposure.]]
A '''circumpolar star''' is a [[star]] that, as viewed from a given [[latitude]] on Earth, never sets below the [[horizon]] due to its apparent proximity to one of the [[celestial pole]]s. Circumpolar stars are therefore visible from said location toward the nearest pole for the entire night on every night of the year (and would be continuously visible throughout the day too, were they not overwhelmed by the [[Sun]]'s glare). Others are called ''seasonal'' stars.

All circumpolar stars lie within a '''circumpolar circle''' whose size is determined by the observer's latitude. Specifically, the angular measure of the radius of this circle equals the observer's latitude. The closer the observer is to the North or [[South Pole]], the larger its circumpolar circle. 

Before the definition of the [[Arctic]] was formalized as the region north of the [[Arctic Circle]] which experiences the [[midnight sun]], it more broadly meant those places where the 'bear' constellations ([[Ursa Major]], the Great Bear, and [[Ursa Minor]], the Little Bear) were high in the sky. Thus the word 'Arctic' is derived from the [[Ancient Greek language|Greek]] {{lang|grc|ἀρκτικός}} ({{lang|grc-Latn|arktikos}}), 'bearish', from {{lang|grc|ἄρκτος}} ({{lang|grc-Latn|arktos}}), 'bear'.