The star Polaris is more commonly known as the North Star or Pole Star because its position in the northern night sky almost exactly marks the Earth's geographic north pole.
An imaginary line drawn through Polaris would run almost exactly through the Earth from the North Pole to the South Pole. It has been long used by sailors to navigate in the northern hemisphere.
Image: An artist's concept of the Polaris triple star system (credit: NASA, ESA, G. Bacon/STScI)
Sir Patrick Moore discusses interesting stars in the evening sky including Alcor, Mizar and Polaris.
Astronomer Mark Thompson shows what you can easily see in the summer night sky.
After pointing out that many people know very little about the night sky, astronomer Mark Thompson helps a group of novices spot summer night sky highlights including the Plough (or Big Dipper), the North Star (Polaris), the summer triangle and the Andromeda galaxy.
Prof Brian Cox demonstrates how we can understand what the entire Universe is made of by looking at the faint light emitted from the stars.
Mark Thompson shows Jonathan Ross how to find the basic constellations.
Mark Thompson shows Jonathan Ross how to find the basic constellations in the night sky, starting with the Plough and the Pole Star.
Sir Patrick Moore and Chris Lintott explain astronomy terms like declination, right ascension and procession.
Polaris (α UMi, α Ursae Minoris, Alpha Ursae Minoris, commonly North Star, Northern Star or Pole Star, also Lodestar, sometimes Guiding star) is the brightest star in the constellation Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star.
Based on measurements from the Hipparcos astrometry satellite, Polaris is estimated to be at a distance of about 434 light-years from Earth. It is a multiple star, consisting of the main star α UMi A, two smaller companions, α UMi B and α UMi Ab, and two distant components α UMi C and α UMi D. α UMi B was discovered in 1780 by William Herschel.
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