Polaris-A slightly variable, supergiant, binary star; the brightest star (Alpha), in the extreme outer end of the constellation Ursa Minor (Little Dipper), with a magnitude of 2.1. Also known as the Pole Star, or North Star. Used for navigation since it is the closest star to the north celestial pole and remains nearly stationary throughout the night. Polaris is primarily used to determine astronomical azimuth and the direction of the celestial meridian. See also pointers.

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Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

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