Heroes, Hounds and Monsters: Myths Told Among the Ptolemaic Stars

Begin with the hunter. The atlas describes Orion as a giant huntsman in myth, slain by the sting of a scorpion sent by the gods, which is why he sets as Scorpio rises. Its recorded sources include the Facts on File Encyclopedia of World Mythology and Legend and Ptolemy's Almagest, which lists it among the 48 ancient constellations.

Canis Major follows at the heel of Orion as one of his hunting hounds. It contains Sirius, the brightest fixed star in the heavens, whose rising once marked the dog days of summer and the flooding of the Nile.

The second hound is small but carries a clue in its name. Procyon, its bright star, means before the dog in Greek, because it rises just ahead of Sirius.

Lepus, the Hare, crouches beneath Orion's feet as the quarry that the hunter and his dogs chase forever across the sky. Its brightest star, Arneb, bears the Arabic word for hare, and the Greeks called the constellation Lagoos.

The second group is built on the largest constellation of all. Hydra winds a great length below the ecliptic, and the atlas records two readings: the many-headed monster of the Lernaean marsh slain by Heracles, or the water snake set in the sky with the Crow and the Cup.

Crater rests on the back of Hydra and is pictured as the goblet of Apollo. In the myth of the Crow, the bird was sent to fetch water in this cup, and the Crow, the Cup and the Serpent were all fixed in the sky together.

Corvus perches on Hydra near Virgo, its four main stars forming a small quadrilateral. In the myth the Crow was delayed by a fig tree on its errand for Apollo, then punished and placed in the sky with the Cup it failed to fill. Ovid's Metamorphoses is among its recorded sources.

The last group turns north. Hercules was long called Engonasin, the kneeling man, before being named for the hero Heracles, shown resting on one knee after his labors. The great globular cluster M13 lies on its flank.

Draco coils between the two Bears around the pole, its head close to Hercules. In myth it is Ladon, the dragon that guarded the golden apples of the Hesperides and was slain by Heracles. The star Thuban in its coils was the pole star of the ancient Egyptians.

Boötes drives the Great Bear around the pole, and its orange star Arcturus means the bear-guard. The atlas records two identities for the figure: Arcas, son of Callisto, or the inventor of the plow rewarded with a place among the stars.

Between Boötes and Hercules lies a neat arc of stars, the Northern Crown. In myth it is the diadem of Ariadne, daughter of Minos, given by Dionysus and cast into the heavens. Its brightest star, Alphecca, is called the jewel of the crown.

End with the hero whose story fills a whole quarter of the sky. Perseus holds the severed head of Medusa, marked by the variable star Algol, and the atlas notes his rescue of Andromeda from the sea monster Cetus, a royal cycle with Cassiopeia and Cepheus.