{"id":55299,"date":"2024-02-27T08:48:20","date_gmt":"2024-02-27T08:48:20","guid":{"rendered":"http:\/\/b1627dc3-c2be-4eac-98d6-c408e4978cb5"},"modified":"2024-02-27T09:32:36","modified_gmt":"2024-02-27T09:32:36","slug":"a-history-of-star-algol-the-winking-demon-star-in-perseus","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/a-history-of-star-algol-the-winking-demon-star-in-perseus\/","title":{"rendered":"A history of star Algol, the winking ‘Demon Star’ in Perseus"},"content":{"rendered":"

An investigation of the myth around the celebrated \u2018winking\u2019 star in Perseus. <\/p>

By Ian Ridpath\n <\/p>

Published: Tuesday, 27 February 2024 at 08:48 AM<\/p>

\n\n

Ask any astronomer to name the most famous variable star<\/a> in the sky and many will say Algol, the eclipsing binary in Perseus whose variations were first reported in 1670 by the Italian astronomer Geminiano Montanari.<\/p>

Algol the ‘Demon Star’ is clearly visible in the evening throughout winter, dropping to one-third of its usual brightness every 2.87 days for 10 hours as it is partially eclipsed by a fainter companion before returning to normal.\u00a0<\/p>

Ask that same astronomer what Algol represents and the answer is likely to be \u2018the winking eye of Medusa\u2019, the Gorgon slain by the Greek hero Perseus in one of the most famous stories of ancient mythology. But is this true?<\/p>

The mythology of Medusa is key to the history of star Algol. Credit: Daniel Villeneuve \/ Getty Images<\/figcaption><\/figure>
Algol and the Almagest<\/strong><\/h2>
The *Almagest<\/em> contained no star charts.<\/p>*
The first illustrated version of the *Almagest<\/em> was produced by the* Arab astronomer<\/a> al-S\u016bf\u012b (better known by the Latinised version of his name, Azophi) over 800 years after the *Almagest<\/em> was written.<\/p>*
Al-S\u016bf\u012b\u2019s *Book of the Fixed Stars<\/em>, published around the year AD 964, adopted the same 48 constellations recognised by Ptolemy, but featured hand-drawn illustrations.<\/p>*
*Still long before the days of printing, these often varied from copy to copy.<\/p>*
*What is reputedly the oldest surviving example of al-S\u016bf\u012b\u2019s book, dated to around AD 1010, visualises Perseus clad in Arabic robes.<\/p>*
$\"In$
In Book of the Fixed Stars from circa AD 1010, held at Oxford\u2019s Bodleian Library, al-S\u016bf\u012b places Algol on the temple of a decapitated head with a beard. Credit: Bodleian Libraries\/University of Oxford<\/figcaption><\/figure>
On this illustration the head of Medusa has become that of a man with a beard, possibly due to the illustrator seeing depictions in which the Gorgon\u2019s dangling snake-hair gave the impression of long whiskers.<\/p>
Algol is the largest of four stars in the head and, crucially, it is placed next to Medusa\u2019s eye, not on it.\u00a0<\/p>
$\"A$ <\/figure>
Chart showing the location of star Algol<\/p>
Algol’s etymology<\/strong><\/h2>
Ptolemy did not give a name for Algol, but the Arabs did. They called it ra\u2019s al-gh\u016bl, \u2018the demon\u2019s head\u2019, from which comes our word Algol, meaning demon or ghoul.<\/p>
It is sometimes suggested that the ghoulish reference arose because Arab astronomers knew of its variability, but al-S\u016bf\u012b made no mention of any such variability, despite the fact that he paid particular attention to star brightnesses and corrected many of the magnitudes assigned by Ptolemy.<\/p>
By calling this star ra\u2019s al-gh\u016bl, al-S\u016bf\u012b and his fellow astronomers were simply translating Ptolemy\u2019s description in the *Almagest<\/em>.<\/p>*
*They did not see it as Medusa\u2019s eye at all.<\/p>*
*Taking all this evidence together, it is clear that there is no evidence that the variability of Algol was known before Montanari announced it in the 17th century.<\/p>*
*Rather, it seems that the name Algol has its origins in Greek mythology and the star\u2019s variability is simply coincidental.<\/p>*
*The idea of Algol being a \u2018winking eye\u2019 is a modern myth.<\/p>*
Algol as a variable star<\/strong><\/h2>
$\"Constellation$
Constellation of Perseus, 1603. From Uranometria by Johann Bayer, 1603. Bayer depicted Algol, as al-S\u016bf\u012b had, near but not on the Gorgon\u2019s eye. Photo by Historica Graphica Collection\/Heritage Images\/Getty Images<\/figcaption><\/figure>
It would take six centuries for western astronomers to make note of star Algol after al-S\u016bf\u012b\u2019s observations, and none of these early depictions showed it as Medusa\u2019s eye.<\/p>
In 1603, German astronomer Johann Bayer published his star atlas *Uranometria<\/em>, labelling Algol as Beta Persei.<\/p>*
*On his illustrated chart of Perseus, Bayer followed al-S\u016bf\u012b\u2019s portrayal, placing Algol on Medusa\u2019s temple next to her right eye, and not on it (see image above).<\/p>*
*The first astronomer recorded as noting Algol\u2019s variability was Montanari in 1670.<\/p>*
*It was only the second-known variable star, 30 years after the brightness of Mira in Cetus was found to also fluctuate.<\/p>*
$\"Image$
Image of Perseus from Atlas Coelestis, a star atlas published posthumously in 1729, based on observations made by the First Astronomer Royal, John Flamsteed. Flamsteed placed Algol on Medusa\u2019s forehead and made no mention of its dipping brightness. Photo by Bridgeman via Getty Images<\/figcaption><\/figure>
However, it seems that initially this fact was either not known or not accepted, as when John Flamsteed, the first British Astronomer Royal, created his star atlas, *Atlas Coelestis<\/em>, in 1729, he made no acknowledgment of its variability.<\/p>*
*He simply listed Algol as a second-magnitude star. He also placed it even higher on Medusa\u2019s forehead than previous depictions.<\/p>*
$\"The$
The star\u2019s variability is noted in Bode\u2019s Uranographia by 1801, but it had travelled even further into Medusa\u2019s snaky locks.<\/figcaption><\/figure>
The variability of Algol, it seems, was lost for many years, until it was rediscovered and explained by the teenage prodigy John Goodricke over half a century later.<\/p>
The next great atlas to be published after this second announcement was Johann Bode\u2019s *Uranographia<\/em> of 1801.<\/p>*
*Bode labelled the star “variabilis”, but he still drew it on the top of Medusa\u2019s head, not on her eye.<\/p> <\/body><\/html>\n*
","protected":false},"excerpt":{"rendered":"
An investigation of the myth around the celebrated \u2018winking\u2019 star in Perseus. <\/p>\n","protected":false},"author":24,"featured_media":55300,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-300x218.jpg",300,218,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-768x558.jpg",768,558,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",800,581,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"An investigation of the myth around the celebrated \u2018winking\u2019 star in Perseus.","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/55299"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/55300"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=55299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=55299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

The mythology of Medusa is key to the history of star Algol. Credit: Daniel Villeneuve \/ Getty Images<\/figcaption><\/figure>
Algol and the Almagest<\/strong><\/h2>
The *Almagest<\/em> contained no star charts.<\/p>*
The first illustrated version of the *Almagest<\/em> was produced by the* Arab astronomer<\/a> al-S\u016bf\u012b (better known by the Latinised version of his name, Azophi) over 800 years after the *Almagest<\/em> was written.<\/p>*
Al-S\u016bf\u012b\u2019s *Book of the Fixed Stars<\/em>, published around the year AD 964, adopted the same 48 constellations recognised by Ptolemy, but featured hand-drawn illustrations.<\/p>*
*Still long before the days of printing, these often varied from copy to copy.<\/p>*
*What is reputedly the oldest surviving example of al-S\u016bf\u012b\u2019s book, dated to around AD 1010, visualises Perseus clad in Arabic robes.<\/p>*
$\"In$
In Book of the Fixed Stars from circa AD 1010, held at Oxford\u2019s Bodleian Library, al-S\u016bf\u012b places Algol on the temple of a decapitated head with a beard. Credit: Bodleian Libraries\/University of Oxford<\/figcaption><\/figure>
On this illustration the head of Medusa has become that of a man with a beard, possibly due to the illustrator seeing depictions in which the Gorgon\u2019s dangling snake-hair gave the impression of long whiskers.<\/p>
Algol is the largest of four stars in the head and, crucially, it is placed next to Medusa\u2019s eye, not on it.\u00a0<\/p>
$\"A$ <\/figure>
Chart showing the location of star Algol<\/p>
Algol’s etymology<\/strong><\/h2>
Ptolemy did not give a name for Algol, but the Arabs did. They called it ra\u2019s al-gh\u016bl, \u2018the demon\u2019s head\u2019, from which comes our word Algol, meaning demon or ghoul.<\/p>
It is sometimes suggested that the ghoulish reference arose because Arab astronomers knew of its variability, but al-S\u016bf\u012b made no mention of any such variability, despite the fact that he paid particular attention to star brightnesses and corrected many of the magnitudes assigned by Ptolemy.<\/p>
By calling this star ra\u2019s al-gh\u016bl, al-S\u016bf\u012b and his fellow astronomers were simply translating Ptolemy\u2019s description in the *Almagest<\/em>.<\/p>*
*They did not see it as Medusa\u2019s eye at all.<\/p>*
*Taking all this evidence together, it is clear that there is no evidence that the variability of Algol was known before Montanari announced it in the 17th century.<\/p>*
*Rather, it seems that the name Algol has its origins in Greek mythology and the star\u2019s variability is simply coincidental.<\/p>*
*The idea of Algol being a \u2018winking eye\u2019 is a modern myth.<\/p>*
Algol as a variable star<\/strong><\/h2>
$\"Constellation$
Constellation of Perseus, 1603. From Uranometria by Johann Bayer, 1603. Bayer depicted Algol, as al-S\u016bf\u012b had, near but not on the Gorgon\u2019s eye. Photo by Historica Graphica Collection\/Heritage Images\/Getty Images<\/figcaption><\/figure>
It would take six centuries for western astronomers to make note of star Algol after al-S\u016bf\u012b\u2019s observations, and none of these early depictions showed it as Medusa\u2019s eye.<\/p>
In 1603, German astronomer Johann Bayer published his star atlas *Uranometria<\/em>, labelling Algol as Beta Persei.<\/p>*
*On his illustrated chart of Perseus, Bayer followed al-S\u016bf\u012b\u2019s portrayal, placing Algol on Medusa\u2019s temple next to her right eye, and not on it (see image above).<\/p>*
*The first astronomer recorded as noting Algol\u2019s variability was Montanari in 1670.<\/p>*
*It was only the second-known variable star, 30 years after the brightness of Mira in Cetus was found to also fluctuate.<\/p>*
$\"Image$
Image of Perseus from Atlas Coelestis, a star atlas published posthumously in 1729, based on observations made by the First Astronomer Royal, John Flamsteed. Flamsteed placed Algol on Medusa\u2019s forehead and made no mention of its dipping brightness. Photo by Bridgeman via Getty Images<\/figcaption><\/figure>
However, it seems that initially this fact was either not known or not accepted, as when John Flamsteed, the first British Astronomer Royal, created his star atlas, *Atlas Coelestis<\/em>, in 1729, he made no acknowledgment of its variability.<\/p>*
*He simply listed Algol as a second-magnitude star. He also placed it even higher on Medusa\u2019s forehead than previous depictions.<\/p>*
$\"The$
The star\u2019s variability is noted in Bode\u2019s Uranographia by 1801, but it had travelled even further into Medusa\u2019s snaky locks.<\/figcaption><\/figure>
The variability of Algol, it seems, was lost for many years, until it was rediscovered and explained by the teenage prodigy John Goodricke over half a century later.<\/p>
The next great atlas to be published after this second announcement was Johann Bode\u2019s *Uranographia<\/em> of 1801.<\/p>*
*Bode labelled the star “variabilis”, but he still drew it on the top of Medusa\u2019s head, not on her eye.<\/p> <\/body><\/html>\n*
","protected":false},"excerpt":{"rendered":"
An investigation of the myth around the celebrated \u2018winking\u2019 star in Perseus. <\/p>\n","protected":false},"author":24,"featured_media":55300,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-300x218.jpg",300,218,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus-768x558.jpg",768,558,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",800,581,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/a-history-of-star-algol-the-winking-demon-star-in-perseus.jpg",1024,744,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"An investigation of the myth around the celebrated \u2018winking\u2019 star in Perseus.","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/55299"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/55300"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=55299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=55299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}