The constellation Perseus was named after the Greek hero who defeated the deadly Medusa. The star Algol (derived from the Arabic "Ras al Ghul", "Head of the Demon") represents the head of Medusa. It shines reddish and changes its brightness between 2.1 and 2.4 mag, which demonstrates the origin of its name.
How to spot Perseus
The stars Mirfak, δ, ε and ζ form the body of Perseus. In his hand he holds the head of Medusa, which is represented by the star Algol. The constellation is circumpolar, so it is visible throughout the year, but best in winter and spring. It lies between the constellations Giraffe, Aries, Cassiopeia, Triangle and Charioteer.
According to Greek mythology, Perseus was the son of Zeus and Danae, daughter of the king of Argos, Ancrisius. Ancrisius exiled his daughter and her newborn on the island of Seriphos, because an oracle had predicted a disaster if he wouldn’t do so. The king of the island accepted the two benevolently but tried again and again to persuade the beautiful Danae to marry. This displeased Perseus, but the king denied his plan to him. Out of relief, Perseus promised his foster father a special gift - the head of Medusa. The look of the Medusa made everyone who caught it to become a stone, which is why the king of Seriphos assumed that Perseus would soon no longer stand in the way of the wedding. Athena, however, who had transformed the once charming Medusa into the monster, provided Perseus with an effective equipment, knowing that he was also a son of her beloved father Zeus. Finally, he managed to defeat Medusa and carry her head with him. On the way home, Perseus passed by the virgin Andromeda, who was chained to a rock by her father, Cepheus, as a sacrifice to the sea monster Cetus. He rescued her and later proposed to her, which Cepheus allowed, although he had promised her to his brother long ago. The brother didn’t want to lose the opportunity of marrying Andromeda and tried to defeat Perseus at the wedding ceremony. Perseus therefore pulled the head of the Medusa out of the opaque bag and turned his rival into stone. With his newlywed wife Perseus moved back to Seriphos just in time to prevent his mother from marrying the king there. On the island he and Andromeda founded a large family. One of his granddaughters was Alkmene, who later became the mother of the hero Hercules.