By Dean Regas
Enquirer Contributor

IF YOU GO

What: Transit of Venus, the first time the planet will cross the sun's disc since 1882. Where: Ault Park Pavilion area, Mount Lookout When: 6-7:30 a.m. Tuesday Sponsor: The Cincinnati Observatory and the Cincinnati Park Board Also: Friends of the Observatory will set up several instruments to view the event. The Observatory will offer refreshments and sell safe viewing glasses for $3. Information: (513) 321-5186; www.cincinnatiobservatory.org.

Despite the muscles, myths and machismo, the constellation Hercules is not very easy to find in the night sky. The brightest stars that make up Hercules are third magnitude stars - dimmer than all the stars in the Big Dipper. Let's face it, he's not very bright.

But locating Hercules in the evening sky can be a rewarding search. Not only will you discover an ancient constellation, but you can learn an entire section of the sky.

You can find Hercules about halfway up in the eastern sky at 10 p.m. His most recognizable stars form a four-sided figure, or keystone shape. From the keystone, two arms and two legs splay out in all directions making the constellation look more like a spider than a he-man. Hercules is said to be kneeling. Unfortunately for him (and our imagination), he is kneeling upside-down.

The ancient Sumerians, who charted the heavens thousands of years ago, thought this kneeling figure represented Gilgamesh, their greatest superhero. The epic of Gilgamesh the warrior is one of the oldest surviving texts. In one chapter, Gilgamesh defeated a fierce she-dragon named Tiamat. He then sliced her massive body in two and created the sky with one half and the Earth with the other half.

Hercules or Herakles

The Greeks called him Herakles. At eight months of age, he killed two serpents that crawled into his nursery. He was schooled by the greatest teacher in Greece, Chiron the centaur, who can be seen in the constellation Sagittarius.

As an adult, Herakles had to complete twelve labors as punishment for killing his first wife. The goddess Hera, his sworn enemy, made sure they were the most impossible things imaginable.

Two of the labors appear in the night sky to the west of Herakles. The first was to slay the terrible Nemean Lion represented by the constellation Leo, which appears in the western sky after sunset above Jupiter - the brightest star like object in the sky right now. You can easily identify Herakles in paintings thanks to his lion skin wrap.

Another labor involved slaying fierce, nine-headed Hydra and an ankle-biting crab (represented by the constellations Hydra and Cancer). These two creatures, along with Leo, form the Herakles pet cemetery of the sky. Herakles eventually completed the twelve labors and achieved his freedom and immortality in the stars. The unique moral became very popular in ancient Greece: Man can overcome all obstacles, even those thrown down from the gods themselves.

Ras Algethi and M 13

The brightest star in Hercules is called Ras Algethi, Arabic for "Head of the Kneeler." The star is a red supergiant 150 times the diameter of our sun. Like most red supergiants, Ras Algethi's brightness varies significantly as it enters the final stage of its life. Aim a small telescope at Ras Algethi and you will discover another hidden secret: it is two stars in one. A small greenish companion slowly orbits the main red star.

The most interesting feature in the figure of Hercules is a fuzzy area in the sky called M 13, a globular cluster of around 300,000 stars which is the brightest of its kind in the northern skies. The M stands for Charles Messier who catalogued over 100 clusters, nebulae and galaxies in the 18th century. You can see M 13 with the naked eye but try viewing it through some binoculars to achieve a sparkling effect. It is located inside the keystone on Hercules' left hip.

Identifying Hercules may not be a Herculean task, but make it one of your labors this summer to visit him in the evening sky.

Dean Regas is the Outreach Astronomer at the Cincinnati Observatory Center. Email: deanobservatory@zoomtown.com