The Constellation
Cancer |
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Mythology and History |
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The Crab. |
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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. |
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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. |
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.
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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. |
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.
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In 1531 Halley's Comet was discovered in this part of the
sky. |
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In the summer of 1895, all of the planets, except Neptune,
congregated here--and extremely rare event. |
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