Orion Nebula, bright diffuse nebula in the constellation Orion; also known as the Great Nebula of Orion and cataloged as M42 or NGC 1976. It is located near the middle of the "sword" hanging from Orion's "belt" of stars. Its central bright region is about 1° in diameter and it has a total extension of 3°. It is about 1,000 light-years distant and as many as 60 light-years in diameter. The nebula is an enormous cloud of gas surrounding a cluster of very hot young stars. To the naked eye the nebula appears to be a faint star but becomes a vague patch of light when viewed through binoculars. The bright region is divided into two sections, the northeast portion being cataloged separately as M43 or NGC 1982. The Orion Nebula is the nearest major site to earth of massive star formation.

Orion, in Greek mythology, Boeotian hunter. When Oenopion delayed giving his daughter Merope to him, Orion, when drunk, violated her. Oenopion then blinded him, but his vision was restored by the rays of the sun. The story of Orion's death has many versions. Some state he offended Artemis, who killed him. Others say that he became her favorite hunting companion, but offended Apollo, who loosed a giant scorpion to chase Orion into the sea. Apollo then tricked Artemis into shooting Orion. When she discovered what she had done, she gave way to her grief and immortalized her companion and the scorpion by placing them in the heavens as constellations.

Orion, in astronomy, constellation located on the celestial equator. It is one of the most conspicuous and easily recognizable constellations in the entire sky. From ancient times it has been mentioned in the literature of many peoples and is traditionally depicted as the figure of a warrior. Four bright stars form a quadrangle marking his shoulders and feet; brilliant red Betelgeuse (Alpha Orionis) at his right shoulder, Bellatrix (Gamma Orionis) at his left shoulder, and dazzling Rigel (Beta Orionis) at his left foot are all among the 25 brightest stars in the sky, while Saiph (Kappa Orionis) at the right foot is of second magnitude. Three bright second-magnitude stars form a belt almost along the celestial equator; hanging from the belt is a sword of dimmer stars and including the famous Great Nebula (M42). Orion reaches its highest point in the evening sky in late January.

Bright nebula, faintly visible to the unaided eye in the sword of the hunter's figure in the constellation Orion. About 1,500 light-years from Earth, it contains hundreds of very hot young stars clustered about a group of four massive stars known as the Trapezium. Radiation primarily from these four stars excites the nebula to glow. Discovered in the early 17th century, it was the first nebula to be photographed (1880).

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In Greek mythology, a powerful hunter. He was sometimes said to be the son of Poseidon. He drove the wild beasts out of the island of Chios and fell in love with Merope, daughter of the island's king. Disapproving of Orion, the king had him blinded, but his vision was restored by the rays of the rising sun. He later went to Crete to live and hunt with Artemis. Some legends hold that he was killed by Artemis or Apollo out of jealousy; another tells that he was fatally bitten by a scorpion. After his death the gods placed him in the sky as a constellation.

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