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Glossary term: North Star

Also known as Polaris, α Ursae Minoris or Pole Star

Description: The North Star is the nearest bright star (within 1 deg.) to the North Celestial Pole. Its official designation is α Ursae Minoris, but it is commonly known as Polaris or the Pole Star. All the stars of the northern hemisphere appear to rotate around it, so it provides an excellent fixed point from which to perform measurements for navigation and astrometry. Its elevation above the horizon gives the approximate latitude of the observing site. However, its position on the celestial sphere is slowly changing due to the precession of the rotation axis of Earth, so in several centuries Polaris will not indicate the locus of the North Celestial Pole anymore. Polaris is a triple star system, involving the brightest known Cepheid variable. Its distance from Earth is about 447 light years.

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Term and definition status: This term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".