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With a father like Zeus, it's no wonder Perseus became one of antiquity's
most notable characters. Even his name ("per Zeus") identifies his lineage.
Zeus had fallen in love with Danae, the beautiful daughter of Acrisius,
king of Argos. An oracle had predicted that Danae would some day bore a son
who would kill the king, so Acrisius hid her in a bronze (or ivory) tower.
But Zeus knew of her beauty, and one day he changed himself into
a shower of gold dust and visited Danae's cell.
When the child Perseus was born, Acrisius put him and his mother in a wooden
chest and threw it into the sea. The wooden chest floated to the island
of Seriphos, where the fisherman Dictys rescued it. He took them to his
brother Polydectes (or Polydeuces), who happened to be the king of
Seriphos. Polydectes raised Perseus to manhood.
Perseus grew to found the city state of Mycenae, on the Peloponnesian
peninsula, and become its first king. At least this is the myth. In
reality, that city was founded at about 3000 BC, and ca 1650 BC to 1400
BC the Mycenaean civilisation was one of the most brilliant in all of
Greece, until its sudden collapse ca 1300 BC.
As for Perseus, he is mostly remembered for one series of adventures:
the killing of the Gorgon Medusa and the rescue of Andromeda.
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The Gorgons were three sisters: Euryale ("wide roaming"), Stheino ("strong"),
and Medusa ("cunning one"). They were originally very beautiful but Medusa
committed an indiscretion with Poseidon one night in a temple of Athene.
This goddess was so enraged over the sacrilege that she changed Medusa into
a hideous monster with huge teeth and protruding tongue, claws in place
of hands, snakes in place of tresses, large wings, and a look that would
turn anyone into stone.
Needless to say, Medusa wasn't terribly popular. Indeed, her head became
the ultimate prize; anyone who could chop it off would be an instant
hero. But none were foolish enough to try. Until Perseus one day made a
casual promise to Polydectes.
The thing was, Polydectes wanted to marry Perseus' mother Danae, but the
king tried to keep his wishes secret by telling Perseus that he wished
to take Hippodameia as a wife. Perseus had suspected the king of lusting
after his mother, so he was quite relieved, so relieved he told him "If
you wish to marry Hippodameia, I will do anything you ask of me. Even
offer you the head of the Gorgon Medusa as a wedding present." "Fine,"
said Polydectes, "that would be a very nice gift indeed".
Athene had been listening; this was the moment she had been waiting for:
someone to strike back at her worst enemy. Athene brought Perseus to
Samos, where the Gorgons were living, and she showed him an image of the
three, so he could distinguish amongst them. Then she warned Perseus to
look at the reflection, never the face, lest he be turned to stone. So
saying, Athene gave Perseus a brightly shining shield.
Perseus had more help in his quest for the Gorgon's head. Hermes gave
him a sickle, but the most important items he got for himself: the
winged sandals, the helmet that would make him invisible, and the magic
wallet (to put the severed head in). To make a rather long story a
little shorter, he managed to steal these items from the Stygian Nymphs,
in the bowels of the earth, where they lived. Thus armed, Perseus set
out to kill Medusa.
Perseus came across the three Gorgons asleep. Looking at his shield, he
carefully studied each figure, making sure it was Medusa who would feel
the blade of his sickle. Quickly then he sliced off Medusa's head and
threw it into the magic wallet.
The winged horse Pegasus instantly flew out of her body. He too had been
conceived by Poseidon in the temple of Athene, but Poseidon had chosen
not let Pegasus come into the world, to placate the goddess. At Medusa's
death, Pegasus was now free.
The Gorgon sisters frantically looked for the killer of Medusa, but the
helmet worn by Perseus rendered him invisible.
With the winged sandals, Perseus made his escape. Again, to shorten the
story considerably, he soon came across Andromeda, naked and chained to
a rock for a terrible sea monster. Perseus quickly made a deal with
Cepheus and Cassiopeia; for rescuing the maiden he would then win her
hand.
After killing the sea monster, and rescuing Andromeda, Cassiopeia changed
her mind about Perseus marrying her daughter. In the battle that followed,
Perseus had to resort to desperate measures. He took the head of Medusa
out of the magic wallet and brandished it. Instantly the warring parties,
including both mum and dad, were turned to stone.
Perseus took his new bride back to Seriphos, where a new threat greeted
him. Danae, his mother, had fled to a temple to avoid marrying
Polydectes. The king was hosting a banquet; Perseus entered the palace
and announced that he had brought the marriage gift, as promised. So
saying, he showed them the Gorgon's head, turning the entire banquet
party to stone. (The island of Seriphos contains a group of boulders
which some still believe to be the petrified remains of the banquet.)
Some time later a discus flung by Perseus during some funeral games
struck his grandfather, Acrisius, and killed him, thus fulfilling the
prophecy, to the shame and sorrow of Perseus himself.
Perseus isn't a very clear asterism; some
forms of the constellation have a straight line from alpha to theta,
perhaps indicating Perseus' sword or sickle that he used to kill
the Medusa.
However, as far back as Ptolemy's time, Perseus was seen as holding the
head of Medusa, with Algol (beta Persei) being the "evil eye" of the Gorgon.
Perseus' stars are fairly bright. A good
many of them go under other than Bayer names; several are notable
binaries. There are also a few fine deep sky objects.
Double stars:
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Epsilon Persei is rather difficult because of the dim companion:
2.9, 8.1; PA 10º, separation 8.8".
Zeta Persei is a multiple system, also with faint companions:
AB: 2.9, 9.5; 208º and separation 12.9".
C is a dim 11.3, PA 286º and separation 32.8";
D is 9.5, 195º, 94.2".
Eta Persei is a fixed triple system; AB are yellow and blue.
AB: 3.8, 8.5; PA 300º, separation 28.3".
C: 9.8; 268º, separation 66.6".
Struve 331 is a splendid fixed binary: 5.4, 6.8; PA 85º,
separation 12.1".
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It's found midway on a line between gamma Persei and tau Persei and just
a bit south.
h1123 is a fine wide binary in the middle of M34: 8.5, 8.5; PA 248º,
separation 20.0".
Variable stars:
Perseus had many types of variable stars, many of which are too small to
notice. Below are some of the more obvious examples.
Beta Persei (Algol) is a notable EA type eclipsing binary, changing
from 2.12 to 3.39 every 2.8673 days (2d, 20h 48m 56s) as the companion
eclipses the primary. The eclipse lasts roughly ten hours.
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The name itself, Al Ghul, means "Mischief Maker"; it is sometimes
called Ras Algol, Ra's al Ghul, "The Demon's Head".
This is a very bright white star, and the first eclipsing binary every
discovered, in 1669 (thus giving the name "Algol variable" to this type
of star). However the theory itself of an eclipsing binary being
responsible for the variations in visual magnitude had to wait until
1783; this theory was only proved correct in 1889.
The whole system is a bit more complicated than one star occulting
another. A third component, Algol C, orbits both A and B about every
1.86 years, and even more companions have been proposed, but not proven.
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R Persei is a long-period variable, 8.1 to 14.8 every 209.89 days.
The next maximum is scheduled for mid May 1997 (then that December). In
2000 the maximum should occur the last week of October.
S Persei is an SRc type variable, 7.9 to 12 every 822 days (2.25
years). The next maximum should occur in the last half of October, 1998.
Deep Sky Objects:
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M34 (NGC 1039) is a fine open cluster containing about eighty
stars. The cluster is considered about 100 million years old.
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The cluster is about five degrees WNW of Algol (beta Persei), or more
precisely twenty-seven arc minutes west of Algol and two degrees north.
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NGC 869 and NGC 884 form the well known "Double Cluster",
two open star clusters side by side, easily seen by naked eye or binoculars.
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The clusters are both considered babies, 869 only being about 6.5
million years old, and 884 about 11-12 million years old.
The easiest way to find them is to form a triangle, using gamma Andromedae
and alpha Persei. Then the northern point becomes the twin clusters.
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NGC 1499, The California Nebula, is a gaseous nebula one degree
north of zeta Persei, and stretching itself in an east-west direction.
Unfortunately it is extremely faint and difficult to view. In fact
binoculars might afford the best chance.
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