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Polaris, Alpha Ursae Minoris, is the bright star closest to the north celestial pole, making it the current north pole star. It is also known as the North Star, the Lode Star, or the Pole star.
Because it lies nearly in a direct line with the axis of the Earth's rotation "above" the North Pole—the north celestial pole—Polaris is apparently motionless from the Earth, and all the stars of the Northern sky appear to rotate around it. Therefore, it makes an excellent fixed point from which to draw measurements for celestial navigation. The antiquity of the use of this star is attested to by the fact that it is found represented on the earliest known Assyrian tablets. At present, Polaris is slightly over 1° away from the pole of rotation and hence revolves around the pole in a small circle about 2° in diameter. Only twice during every 24 hours does Polaris accurately define the true north azimuth; the rest of the time it is only an approximation and must be corrected using tables.
Although Shakespeare wrote "I am as constant as the northern star", due to precession of the equinox, other stars in the northern hemisphere have been and will likely again become the north star over thousands of years; Thuban was pole star in the past, and Vega will be in the future.
It is easy to find Polaris by following the line traced from Merak to Dubhe (β and α Ursae Majoris, also known as the Pointers), the two stars at the end of the bowl of the Big Dipper. One can also follow the central point of the W shape of CassiopeiaCassiopeia Abbreviation Cas Genitive Cassiopeiae Meaning in English the Queen Right ascension 1 h Declination 60° Visible to latitude Between 90° and -20° Best visible November Area Total Ranked 25th598 sq. Stars with apparent magnitude • Shedir (α).
Polaris's fame as the North Star has given rise to a persistent misconception that it is the brightest star in the sky. Although Polaris is a relatively bright and conspicuous star, it is nowhere near the brightest; it is actually the 51st brightest star. The brightest star in the sky (besides the SunThe Sun (also called Sol is the star in our solar system. Planet Earth orbits the Sun. Other bodies that orbit the Sun include other planets, asteroids, meteoroids, comets and dust. Not all objects passing through the solar system have been orbitally capt) is SiriusThis article is about the star. See Sirius (disambiguation) for other uses of the name. Sirius ( α Canis Majoris, also known as the Dog Star is the brightest star (−1. 46m) in the night sky. This star can be seen from every inhabited region of. See List of brightest stars100 Brightest stars as seen from Earth (by apparent magnitude). The exact order of this list is not completely well defined: Double stars here are treated individually while other lists may combine their brightness. Statistical variations in measured valu.
Polaris is 431 light yearA light year abbreviated ly is the distance light travels in one year: roughly 9. 46 × 1012 kilometres (9. 46 petametres, or about 5. 88 × 1012 miles). More specifically, a light year is defined as the distance that a photon would travel, in free space ans (132 parsecThis article is about the unit of length. In computer programming, Parsec is an XML syntax analyzer, like Lark, or a parsing library for the Haskell programming language. There's an open source computer game named Parsec . The parsec (abbreviated pc is as) from Earth, according to measurements made by the Hipparcos satellite. It is an F7 supergiant (Ib) or bright giant (II), with two smaller companions: an F3 V main sequence star about 2000 AUThe astronomical unit AU is a unit of distance, approximately equal to the mean distance between Earth and Sun. The currently accepted value of the AU is 149,597,870,691+-30 metres (about 150 million kilometres or 93 million miles). Earth's orbit is not a away and a close companion in an orbit with a 5 AU semi-major axis. The main star is a Population II cepheid variable, the pulsations of which cause it to cycle steadily. Around 1900, the star varied between being 8% brighter than its average luminosity and 8% dimmer (0.15 magnitudes in total) with a 3.97 day period. Now ( 2004), the variations are about 2% from peak to trough. The star is also about 15% brighter (on average) than it was in 1900; the period has also lengthened by about 8 seconds each year since then. Recent research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it. Astronomer Edward Guinan considers this to be a remarkable rate of change and is on record as saying that "If they are real, these changes are 100 times larger than [those] predicted by current theories of stellar evolution".
There is no real south star. The star, visible to the naked eye, that is closest to the south celestial pole is the dim Sigma Octantis. However, the bright Southern Cross ( Crux) points towards the south celestial pole.
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