Orion, the Hunter

Ori

Orionis

Sky Chart and Artist Rendering of Orion

Origin:
While the Big Dipper of Ursa Major may very well be the best known asterism, Orion is possibly the best known and most recognized constellation.  The star group was known by its present name by about 500 BC although it has variously been associated with a god, hero, hunter, and warrior.  The constellation is steeped in a variety of western legends.

The Chinese included Orion in a larger constellation representing the Tiger. To the ancient Egyptians and Phoenicians he was the Sun-god. The Jews identified him as the Giant or Nimrod (sent to the celestial sphere for rebelling against the Lord). To the Hindus, the constellation represented a Stag.  Other cultures have seen turtles, octopus, cayman, and alligator-like creatures.

Information:
Orion is a large, very easy to find winter constellation which crosses the southern meridian at 9 pm on January 26. Except for the head star (Meissa, Lambda Orionis), the outline of the body has no stars fainter than magnitude 2.1. The bright belt stars dip to only a minimum brightness of magnitude 2.3. It takes little imagination to see the standing figure of Orion with his bow extended to the west and his other arm over his head, as if he just let loose an arrow.  Orion is situated south of Taurus the Bull and north of Lepus the Hare.  The celestial equator passes through Orion's belt; thus, the constellation is visible to both northern and southern hemisphere observers (albeit Orion is standing on his head when viewed from the southern hemisphere).

The interesting objects in Orion are so numerous that it would be impossible to describe them all in a limited space.  Betelgeuse, Alpha Orionis, (Arabic for "arm-pit") is the upper-left "shoulder" star.  Betelgeuse is an conspicuously orange-red supergiant star.  The lower-right foot star is Rigel, Beta Orionis, and is a blue supergiant star 57,000 times more luminous than the Sun, if both were observed at the same distance.  Betelgeuse is one of the three stars in the "Winter Triangle", the others being Sirius (Canis Major) and Procyon (Canis Minor).

The showpiece deep sky object in Orion is the Great Nebula (M42, NGC 1976).  Found easily as the middle star of the "sword" hanging from Orion's belt, the Great Nebula is a stellar "nursery" containing many very young stars. The nebula is visible with naked eye as a "fuzziness" in the sword, but in a telescope of even modest size, the nebula is an amazing glowing cloud of gas with incredible detail. The Great Nebula is arguably the most photographed deep sky object in the heavens.

Mythology:
Orion was the son of Poseidon, the god of the seas and the sea-nymph Eurayle. Two western myths have endured the test of time.  In one, Orion boasted that his prowess as a hunter was so great that he could kill all the animals on the face of the Earth.  Such an arrogant statement alarmed Gaea, Goddess of Earth and matriarch to the Titans, so she decided that Orion must die just in case he might one day decide to demonstrate his claim.  Gaea created and sent a giant scorpion - Scorpius, by name - with orders to sting to Orion. As mighty as Orion was, he found that none of his mortal weapons could slay the monster and, after only a brief battle, the scorpion managed deliver a fatal sting on the hunter's heel (Rigel). Orion and the Scorpion were each honored for eternity as constellations in the sky but, to prevent any lasting hostilities, they were placed at opposite ends of the starry sphere -- as Orion rises in the east, Scorpius sets in the west.

In another Greek myth, the goddess Artemis (goddess of Wild Animals and the Moon) fell in love with the great hunter and handsomest man alive, Orion.  Noticing that Artemis was spending a great deal of time hunting with Orion and not approving of her choice of would-be lovers her brother, Apollo, schemed to eliminate Orion.  One day while Orion was swimming, Apollo and Artemis walked by the lake.  Knowing her excellent skill with the bow, Apollo challenged her to hit the target bobbing in the water. Artemis, not knowing the identity of the target, took aim and loosed an arrow into the   head of Orion and killing him. Artemis was horrified when she discovered who she had killed and her shock was made more so when she learned that she had been tricked by Apollo.  In great sorrow and misery she carried Orion's body high up into the sky aboard her silver Moon-chariot.  She left his body in as dark a place she could find so that his stars would shine the brightest of all surrounding stars, and he remains where we see him today.