Hercules, Legendary Hero
By Ellis Myers
The constellation Hercules is almost directly overhead in the early evenings
in early summer. The fifth largest of all constellations, it lies between the
easily recognizable Corona Borealis and the equally familiar Lyra. It extends
on the north from Draco to Ophiuchus in the south. Find it by looking about
a third of the way from Vega toward Arcturus, where you will see its central
geometric trapezoid. The full star pattern is not easy to trace, although the
constellation is one of the oldest identified sky figures and, in earlier forms,
was known in Assyrian texts in 3000 bc.
In the land of the Euphrates, these stars were looked upon as their Sun god,
Izhbudar. Like Hercules, Izhbudar was credited with unbelievable exploits, and
his position in the sky shows him as he slays the dragon, Draco. In Babylonia
it was Gilgamesh, also a mighty hero whose prowess in battle against the monsters
paralleled those of the later Hercules. Likely the early myths gradually changed
into the familiar twelve labors of Hercules.
Hercules was the son of Jupiter and the mortal Alcmene and so he was also a
mortal, but with semi-divine and superhuman strength. Juno, jealous of Jupiter's
many sons by mortal women, had made Hercules a slave to King Eurystheus. First,
Hercules strangled the Nemean lion. The spirit of the lion was rescued by Jupiter
and returned to the heavens as the constellation Leo. The second task was to
destroy the Hydra. This enormous reptile had nine heads, the middle one immortal.
If any of the other eight was cut off two more regenerated in its place. Hercules
solved this problem by burning the heads, except for the immortal one, which
he buried under a large rock, where it presumably still lies dormant. Again,
Jupiter transported the fallen beast to the skies, and Hydra can be found to
the south of the Lion. Then, Hercules was ordered to kill some horrid birds,
the Stymphalides; he accomplished this with the help of his benefactor, Minerva.
In the sky, near Hercules, can be found Aquila, the eagle, and Cygnus, the swan-which
may represent the Stymphalian birds-as well as Sagitta, perhaps the arrow Hercules
used for this exploit. To clean the Augean stables, which housed three thousand
oxen and had not been cleaned in thirty years, Hercules diverted two rivers
and managed the job in just a day. Later, he fought the river-god Achelous and
won the hand of the beautiful maiden Deianira. The marriage was not happy, however,
and, thinking that Hercules had fallen in love with a servant girl, Deianira
bewitched him and caused his death. His mortal body was transformed by Jupiter
into the constellation, while his soul joined the immortals on Mount Olympus.
The stories continue, and continue to change and evolve, most recently revised
by Disney Studios.
None of the stars in Hercules is very bright, but in a dark sky the four "keystone"
stars form one of the most recognizable early-summer asterisms. South of this
star group is a splendid red star, Ras Algethi (a-Herculis), an irregular variable
binary, one of the largest stars we know about. The brightest star in the constellation
is b-Herculis, Korneforos, the Club-bearer. This is a magnitude 2.8 spectroscopic
binary with a period of 410 days. Marfik [Marfak] is k-Herculis, a yellow and
light garnet double star that, with a number of other pretty double stars in
this region, makes Hercules an interesting constellation for backyard astronomers
at this time of year.
The most well-known
feature in this area of the sky is the globular cluster M13. A fuzzy patch of
light to the unaided eye, it gives evidence to its hundred thousand or more
stars when observed with a small telescope. The cluster was first pointed out
by Edmund Halley in 1714, and so is sometimes known as Halley's Nebula, for
it was at first thought to be a nebula. Charles Messier listed it as M13 in
1764. For a truly magnificent view of this celestial object arrange to see it
through a larger telescope-photographs cannot show the true wonder of such a
cluster since the concentration of light at the center inevitably exceeds the
contrast range that film can record. Another object of interest is M92, a globular
cluster, a bit smaller than M13, but worth the hunt. From M13 go 6.5° east
and 6.7° north to find it.