Everybody knows the myth about Perseus and Medusa. The four stars which represent her head (beta, pi, ro, omega Persei) and which are called gorgoneio (Hipparch. in Ar. 2,3,27; Ptol.,alm. 7,4) are absorbed by a small tongue of the Milky Way.Among them the most brilliant is the b Persei, usually called Caput Medusae.
The Greek myth has been expressed in a meteorological key (cfr. Quintus Sm. 14,454-458), seeing that Medusa and her sisters, horrible and dark monsters who live in the gloom of the West impersonate the clouds of the storm (1). During the cloud of the storm which forms on the sea (Serv. ad Aen. 5,823; ad Georg. 4,403)- beatiful Medusa was loved by Poseidon and she united with him in "a soft prairie among the spring flowers" (Hes. thg. 278; cfr. Ovid. met. 4,798; 6,119).Consequently Perseus's victory indicates the triumph of the solar hero who kills the demon of the storm and of the lightning (2).Generally the ancients believed that the lightning petrified and in several qabbalistic scripts the rocks with Medusa's head carved on them have the apotropaic value against the ligthing, the storm and demons'attacks (3). However , if the gorgoneio protects from the evil eye it can also bring death : Persephone sends the monster's head to those who he wants to kill.(Hom. Od.12,634) (4).
b Persei is a variable star and there is no other star in the sky which variation would be so sudden. This phenomenon was discovered by Montanari at the end of theXVII century, demostrated then by John Goodricke jr. from York in the 1782 and reasserted by Pickering in the 1880.Algol is a binary star subjected to eclipse. It is composed of two celestial bodies: one brilliant and another lusterless. Its light remains more or less steady to our eyes for two days and a half, at the visual magnitude of 2,3; but before the third day begins it declines, first slowly and then quickly at the visual magnitude of 3,5. It remains in this sudden gulf for no more than two hours and it returns to its maximal brightness very quickly ,in three hours and a half.
Whether in the Greek tradition the b Persei is Medusa's head, the Arabs call this star al-Ghûl, or 'the malignant spirit', 'the devil', 'the ghost', 'the frightful phantom', 'the ogre', 'the cannibal'. Al-ghûl is the Ogre who leads out the travellers of the right way and devours them beginning from the feet. The word derives from ghâla, "to enrapture", "to put someone to death" and this verb means, in his third form (mughâwala), "to take various forms". In Enoch's version of the hermetic de XV stellis , Algol's figure is a human head with a long beard, a virile head, not feminine, with a blood-stained neck (5).To this image and to his name must be referred the Maghrebin legend gathered by Joaquin Garcia Campos in Tetuan which says that " the famous variable star Algol is but a lamp which The Flower of Love (Naûrat ash-shaq) following the advice of Perseus , her faithful lover, has put in the dormer window of her cave. The Flower of Love was the adored and beatiful Orcus' slave who in spite of gifts and caresses was unable to make her his.She made Orcus believe that the lamp's light was shining only in order to guide him in the darkness of the night when he was coming back from hunting and that she would put it out little by little when he would come in the cave. Every time when the young beloved saw that al-Gol , her master was coming back from hunting step by step she covered the lantern with more and more veils until it seemed out. The lack of light warned then her lover about the danger: Orcus was there! However when he went back haunting the veils were raised one by one and gradually the lantern returned to shine again.Then Perseus rushed to Naura's arms and love deified the cave again.Yet the lovers have been once unexpectedly taken by surprise by Orcus. He was out of his mind because of jealousy and attacked the unprepared lovers and managed to kill the slave , but he was also killed by her beloved who flew into a rage and cut Orcus' throat and since then he holds the monster's head in his hand, seizing it by the hair.In memory of his unforgettable lover and in order to revere her, Perseus , faithful to his Naura far beyond the death continues perpetually to light and to put out the lantern which has given light to his lost happiness"(6).
Franz Boll ,in his beautiful essay about the colours of the stars , observes that the majority of the variable stars may be classified as red or reddish, but Algol is an exception and has a clear white light (7); nevertheless as-Sufi says that it shines with a red light (8) and it is also classified as red (or bright red) in the hermetic De XV stellis (9). According to Ptolemy (quadr. I, 9) Algol's nature is similar to that of Jupiter and Saturn, as a whole of the stars of Perseus' figure (10). Being so if it rises or culminates it brings "the rich and those who have a lot of wealth and properties in different regions and cities and are country and costruction lovers. And if the Moon observes one of these stars (having the nature of Jupiter and Saturn) as they rise or culminate, the natives have excellent morals, respect old people, have noble feelings, are generous, tolerant, wise and family lovers" (11).
In particular case if Mars rises or culminates with Algol it makes the person very quarrelsome (12).This star is one of the most powerful of the whole starry sky in the nativities and in the beginnings of the actions. Its stone is the diamond, Saturn's stone (Catalogus Codicum Astrologorum Graecorum, XI/2, p. 119) and thanks to its hardness the other stones may be cut and its virtues are boldness , animosity and the protection of the limbs (13). Its herb is the 'helleborus niger", a poisonous plant, sporadical in woody places which rises from the plain to the mountain tops and blossoms from December until March.If you put a little bit of this herb with some artemisia under the diamond , "you will be able to take your revenge on anyone you want (14).John Gower says: "I heard that its nature is Saturnian, but its character agrees with that of Jupiter. Its stone is the diamond and its plant is the hellebore which is malignant and murky. The plant and the stone are consonant". (15).
It is the star of animosity , boldness and power also according to the astrologers of the Renaissance; if it culminates with Jupiter, remarks G. Stadio, it gives the power on other people's life and death. The same thing if it culminates with the Sun and if Jupiter testifies it (16). Cardano states, during his stay in Scotland, that if it moves together with Mercury in its daily motion it means the priesthood and the authority in law administration (17). It also arouses cruelty and violence according to Origanus (18). United with the Moon's lot it threatens the forfeiture of the goods or their waste (19).