Circumpolar star
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Circumpolar_stars.jpg
Such a definition implies that different stars can be defined as circumpolar at different Earth latitudes. For example, to an observer place right at the Earth's North or South Pole, virtually all the stars are circumpolars. For an observer exactly on the equator, no star can be defined circumpolar, as the pole itself is on the horizon. At different latitudes, an intermediate situation makes some stars circumpolars and others not.
On the northern hemisphere all circumpolar stars rotate around the North Star Polaris, which itself is almost stationary, always at the north (i.e., the azimuth is 0°), and always at the same altitude (angle from the horizon), equal to the latitude of the point of observation on Earth.cs:Cirkumpolární souhvězdí de:Zirkumpolar (Astronomie) it:Circumpolare nl:Circumpolair