lundi 28 juillet 2008

Cancer 5


Scholars believe that astrologers later added the crab to the myth in order to have the Twelve Labors of Hercules reflect the Twelve Signs of the Zodiac. While it is difficult to associate all of Hercules' labors with the zodiac, it is true that the crab figured in Hercules' Second Labor, and is in fact the Second Sign of the Zodiac. In any case, apparently for following its masters command and sacrificing its life, the crab was awarded with a heavenly home. But, because Cancer failed to defeat Hercules, the gods did not give Cancer bright stars to mark the constellation.


Galileo was the first to study its stars with a telescope. He counted over forty members, putting to rest the idea of its nebulosity and introducing the idea of star clusters. There are over three hundred stars in the Beehive. It has been estimated that over a hundred of its stars are brighter than our Sun, and in fact if the Sun were a member of this group, it would be a very modest member indeed, at about 10.9 magnitude.


The name comes from the Latin "cancer," means crab. Cancer joined the dreaded Hydra in battle against Hercules. It was only a bit part, but one which secured its immortality.


The swamps of Lerna was home of the Hydra, an enormous water snake with nine heads (one of which was immortal), and with breath that would kill on contact. With the help of Athene, Hercules located the monster's lair, and the ensuing struggle was a standoff. When one head was sliced off, another appeared in its place. Then at Hydra's plea, a giant crab emerged from the swamp and bit into Hercules' foot. Hercules promptly killed the animal and then cut off the Hydra's immortal head, killing it as well. He then dipped his arrows in the Hydra's blood. The slightest scratch from one of these arrows would bring instant death to his enemies.


M44 (NGC 2632) is better known by the name the Beehive Cluster, or the Latin equivalent, Praesepe, which not only means a hive but also a crib, or manger. This is a bright open cluster clearly visible to the naked eye on a dark enough night, and best appreciated with binoculars or small scope. One of the largest clusters, its 1.5 degree size is equivalent to three full moons end-to-end. Its distance is calculated at between 520-590 light years. This grouping is so large it was well-known in antiquity, when it was thought to be a nebula. The cluster often served to predict the weather: if not crystal clear inclement weather might be on the way.


In 1531 Halley's Comet was discovered in this part of the sky.


In the summer of 1895, all of the planets, except Neptune, congregated here--and extremely rare event.

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