Cancer (constellation)

Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is (Unicode ♋). Cancer is small and its stars are faint. It lies between Gemini to the west and Leo to the east, Lynx to the north and Canis Minor and Hydra to the south.

Notable features

Named stars

Planetary system

55 Cancri is a quintuple planet system with four gas giants and one terrestrial planet which has temperatures likely to allow the existence of liquid water and potentially the conditions to sustain life.

Deep-sky objects

Cancer is best known among stargazers as the home of Praesepe (Messier 44), an open cluster also called the Beehive Cluster or the Gate of Men, which contains the star ε Cancri. The smaller, denser open cluster Messier 67 can also be found here.

History

Cancer is said to have been the place for the Akkadian Sun of the South, perhaps from its position at the summer solstice in very remote antiquity. But afterwards it was associated with the fourth month Duzu (June–July in the modern western calendar), and was known as the Northern Gate of Sun.

Showing but few stars, and its brightest stars being of only 4th magnitude, Cancer was often considered the "Dark Sign", quaintly described as black and without eyes. Dante, alluding to this faintness and position of heavens, wrote in Paradiso:

Illustrations

The modern symbol for Cancer represents the pincers of a crab, but Cancer has been represented as various types of creatures, usually those living in the water, and always those with an exoskeleton.

In the Egyptian records of about 2000 BC it was described as Scarabaeus (Scarab), the sacred emblem of immortality. In Babylonia the constellation was known as MUL.AL.LUL, a name which can refer to both a crab and a snapping turtle. On boundary stones, the image of a turtle or tortoise appears quite regularly and it is believed that this represent Cancer as a conventional crab has not so far been discovered on any of these monuments. There also appears to be a strong connection between the Babylonian constellation and ideas of death and a passage to the underworld, which may be the origin of these ideas in much later Greek myths associated with Hercules and the Hydra.^[1] In the 12th century, an illustrated astronomical manuscript shows it as a water beetle. Albumasar writes of this sign in the work published in 1489 as a large crayfish. Jakob Bartsch and Stanislaus Lubienitzki, in the 17th century, described it as a lobster.

Names

In Ancient Greece, Aratus called Καρκινος (Karkinos), which was followed by Hipparchus and Ptolemy. The Alfonsine tables called it Carcinus, a Latinized form of the Greek word. Eratosthenes extended this as Καρκινος, Ονοι, και Φατνη: the Crab, Asses, and Crib.

The Indian language Sanskrit shares a common ancestor with Greek, and the Sanskrit name of Cancer is Karka and Karkata. In Telugu it is "Karkatakam", in Kannada "Karkataka" or "Kataka", in Tamil Karkatan, and in Sinhalese Kagthaca. The later Hindus knew it as Kulira, from the Greek Κολουρος (Koloyros), the term originated by Proclus.

In Ancient Rome, Manilius and Ovid called the constellation Litoreus (shore-inhabiting). Astacus and Cammarus appear in various classic writers, while it is called Nepa in Cicero's De Finibus and the works of Columella, Plautus, and Varro; all of these words signify crab, lobster, or scorpion.

Athanasius Kircher said that in Coptic Egypt it was Κλαρια, the Bestia seu Statio Typhonis (the Power of Darkness). Jérôme Lalande identified this with Anubis , one of the Egyptian divinities commonly associated with Sirius.

Mythology

Cancer the giant crab, plays a minor role in the Twelve Labors of Hercules. While Hercules was busy fighting the multi-headed monster, Lernaean Hydra, the goddess Hera, who hated her step-son Hercules, sent the Crab to distract him. Cancer tried to kill Hercules, but Hercules kicked Cancer so hard that the crab was sent into the sky.

By other accounts, Cancer grabbed onto the hero's toe with its claws, but barely breaking the rhythm of his great battle with Hydra, Hercules crushed the crab with his foot. Hera, grateful for the little crustacean's heroic but pitiful effort, gave it a place in the sky; but none of its stars were bright because the crab had failed to accomplish its given task.^[2] Some scholars have suggested that Cancer was a late add-on to the myth of Hercules to make the Twelve Labors correspond to the twelve signs of the Zodiac.^[3]

Astrology

As of 2002^[update], the Sun appears in the constellation Cancer from July 21 to August 9. In tropical astrology, the Sun is considered to be in the sign Cancer from June 21 to July 21, and in sidereal astrology, from July 16 to August 15.

Equivalents

In Chinese astronomy, the stars of Cancer lie within the The Vermillion Bird of the South (南方朱雀, Nán Fāng Zhū Què).^[4]

See also

Cancer (Chinese astronomy)

References

• Star Names: Their Lore and Meaning, by Richard Hinckley Allen, Dover. ISBN 0-486-21079-0
• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.
• Dictionary of Symbols, by Carl G. Liungman, W. W. Norton & Company. ISBN 0-393-31236-4

External links

• The Deep Photographic Guide to the Constellations: Cancer
• Star Tales – Cancer

Coordinates: 09^h 00^m 00^s, +20° 00′ 00″