Cancer (The Crab)

The story of the celestial Crab named Cancer brings us to the adventures of Hercules and his twelve ardous labors. The heroic Hercules was another son of Zeus, born illegitimately of a mortal mother.
Hera, wife of Zeus, jealous of this divine infidelity, decided to take revenge on the boy and invoked many terrible punishments against the young hero, including madness; finally, she made him a slave of a Greek King who imposed him 12 jobs. If he managed to accomplish them all, he would be free.
The second job was to kill Hydra of Lerna, hideous swamp creature whose breath was poisonous, huge body and 8 or 9 snake heads. If the center head was cut, it immediately grows back twice as big.
Hera, watching the fight between Hercules and Hydra, decided to intervene in favor of Hydra and sent a giant hero to distract the hero with his pincers. Cancer, the Crab, was rewarded for this action despite it was useless, and Hera gave him a place among the stars close to another victim of Hercules: the Lion.


Cancer is a constellation lacking of bright stars. Cancer’s sky area extends major part of the line that ties Geminorum with Regulus or Leonis. It limits to the north with Lynx; to the east with Gemini and Canis Minor; to the south with Hydra and to the west with Leo. It lies between parallels 10° and 30°, therefore, visible from November to April in northern hemisphere and during the austral summer in southern hemisphere. The ecliptic crosses the constellation in the end of July and the first days of August.


The main stars forming this constellation are:
• Acubens: or Alpha Cancri. Its name comes from the Arabic, meaning “the claw”.
• Al Tarf: or Beta Cancri. Its name comes from the Arabic, meaning “the eye” or “the glance (of Leo)”.
• Ascellus Borealis: or Gamma Cancri. Its name comes from the Latin, meaning “northern donkey”. This name refer to the proximity of an open cluster which name is “the manger”.
• Ascellus Australis: or Delta Cancri. Its name comes from the Latin, meaning “southern donkey”.


Other objets

M 44 or the Praesebre, wonderful cluster of 3.10 magnitude combine at first visible. The ass of north or g and the ass of the south or d are between . Bayer astronomer observed it as a star and catalogued as and Cancri whose star is immersed in the cluster. Galileo solved this agglomeration contanto 36 stars. But already he was famous in the antiquity, in fact, Pliny the Old one mentions it like trustworthy indicator of the metereológico time. It is a physical system distributed on a relatively great zone 95' of arc. Light of us is to 590 years and moves to todsas stars of the accumulation to a 27 speed of km/s. Tiene an age of 660 million years.

M 67, another precious cluster located to the south of the constellation, formed by five hundred stars that are to 2400 years light of us. He is much more old that the Manger, its age is considered in 3.900 million years. It has an angular diameter of 30' of arc.