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[[Image:Position Beta.png|thumb|right|250px|Location of Algol (Beta Persei) in the constellation of Perseus.]]

'''Algol''', also known as '''Beta Persei''', is a triple star system located 92.8 light years away in the constellation of [[Perseus]]. A star system that has been well know throughout [[human history]], it is also the first and most well known eclipsing binary. Normally Algol's apparent magnitude is 2.1, but every 2 days, 20 hours, and 49 minutes, the magnitude drops to 3.4 for some 10 hours. This is due to Algol A (Beta Persei A) being regularly eclipsed from our point of view, by the dimmer Algol B (Beta Persei B).<ref>http://csep10.phys.utk.edu/astr162/lect/binaries/algol.html</ref>

'''Algol''', also known as '''Beta Persei''', is a triple star system located 92.8 light years away in the constellation of [[Perseus]]. A star system that has been well know throughout [[human history]], it is also the first and most well known eclipsing binary. Normally Algol's apparent magnitude is 2.1, but every 2 days, 20 hours, and 49 minutes, the magnitude drops to 3.4 for some 10 hours. This is due to Algol A (Beta Persei A) being regularly eclipsed from our point of view, by the dimmer Algol B (Beta Persei B).<ref>http://csep10.phys.utk.edu/astr162/lect/binaries/algol.html</ref>

==Algol in History==

==Algol in History==

The Algol star system was know at least since antiquity. The [[Ancient Greeks]] called Algol the "Evil eye" of [[Medusa]], this was most likely due to the regular occurrences of the change in brightness and color as Beta Persei B eclipsed Beta Persei A. The name Algol itself is derived from the [[Arabic]] term أس الغول ''ra's al-ghūl'', meaning the Demon's Head or the Head of the Ogre. The name likely this stems from the [[Greek]] view of the star system, specifically Ptolemy, who named it as ''τῶν ἐν γοργονίῳº ὁ λαμπρός'', meaning "the bright one of those in the Gorgon's head". The names "Blinking Demon" and "Demon Star" are [[English]] translations of the Arabic name.<ref>Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (revised edition). Dover. pp. 332–33. ISBN 0-486-21079-0. OCLC 185804232 637940</ref>

The Algol star system was know at least since antiquity. The [[Ancient Greeks]] called Algol the "Evil eye" of [[Medusa]], this was most likely due to the regular occurrences of the change in brightness and color as Beta Persei B eclipsed Beta Persei A. The name Algol itself is derived from the [[Arabic]] term أس الغول ''ra's al-ghūl'', meaning the Demon's Head or the Head of the Ogre. The name likely this stems from the [[Greek]] view of the star system, specifically [[Ptolemy]], who named it as ''τῶν ἐν γοργονίῳº ὁ λαμπρός'', meaning "the bright one of those in the [[Gorgon|Gorgon's]] head". The names "Blinking Demon" and "Demon Star" are [[English]] translations of the Arabic name.<ref>Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (revised edition). Dover. pp. 332–33. ISBN 0-486-21079-0. OCLC 185804232 637940</ref>

In [[Hebrew]] legend, the star was seen as ''Rōsh ha Sāṭān'' or 'Satan's head'. It was also linked with the mythical [[Lilith]]. In Latin it was called ''Caput Larvae'', or 'Spectre's Head'.<ref name="penelope">http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Perseus*.html</ref> [[Medieval]] [[Europe|Europeans]] saw Algol as one of the 15 Behenian stars used for [[astrology]].<ref>Tyson, Donald; Freake, James (1993). Three Books of Occult Philosophy. Llewellyn Worldwide. ISBN 0875428320. OCLC 26634250 41597186</ref> The [[Chinese]] named the star 大陵五, meaning the Fifth Star of the Mausoleum, although they also named it 叠尸 or ''Tseih She'', meaning 'Piled up corpses'.<ref name="penelope">http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Perseus*.html</ref>

In [[Hebrew]] legend, the star was seen as ''Rōsh ha Sāṭān'' or '[[Satan|Satan's]] head'. It was also linked with the mythical [[Lilith]]. In Latin it was called ''Caput Larvae'', or 'Spectre's Head'.<ref name="penelope">http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Perseus*.html</ref> [[Medieval]] [[Europe|Europeans]] saw Algol as one of the 15 Behenian stars used for [[astrology]].<ref>Tyson, Donald; Freake, James (1993). Three Books of Occult Philosophy. Llewellyn Worldwide. ISBN 0875428320. OCLC 26634250 41597186</ref> The [[Chinese]] named the star 大陵五, meaning the Fifth Star of the Mausoleum, although they also named it 叠尸 or ''Tseih She'', meaning 'Piled up corpses'.<ref name="penelope">http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Perseus*.html</ref>

The first known recording of Algol's regular variation in its magnitude was in 1667 by Geminiano Montanari. In May 1783, John Goodricke presented his findings on the proposed cause of Algol's variability to the Royal Society. He believed a dark body regularly passed in front of the star, or that the star itself has some dark spot.<ref>http://www.surveyor.in-berlin.de/himmel/Bios/Goodricke-e.html</ref> It wasn't until 1881, when Edward Pickering, an astronomer from [[Harvard]], brought forth evidence that Algol was an eclipsing binary star system.<ref>http://adsabs.harvard.edu/abs/1881AReg...19..253.</ref> This was confirmed in 1889 by Hermann Carl Vogel, who discovered periodic [[Dopper Shift|Doppler shifts]] in the spectrum of Algol A and the eclipsing Algol B.<ref>http://adsabs.harvard.edu/abs/1989SSRv...50....1B</ref>

The first known recording of Algol's regular variation in its magnitude was in 1667 by Geminiano Montanari. In May 1783, John Goodricke presented his findings on the proposed cause of Algol's variability to the Royal Society. He believed a dark body regularly passed in front of the star, or that the star itself has some dark spot.<ref>http://www.surveyor.in-berlin.de/himmel/Bios/Goodricke-e.html</ref> It wasn't until 1881, when Edward Pickering, an astronomer from [[Harvard]], brought forth evidence that Algol was an eclipsing binary star system.<ref>http://adsabs.harvard.edu/abs/1881AReg...19..253.</ref> This was confirmed in 1889 by Hermann Carl Vogel, who discovered periodic [[Dopper Shift|Doppler shifts]] in the spectrum of Algol A and the eclipsing Algol B.<ref>http://adsabs.harvard.edu/abs/1989SSRv...50....1B</ref>