Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.
Orion, in Greek mythology
Orion, in astronomy
Orion(or-ÿ -ŏn, oh-rÿ ) A very conspicuous constellation on the celestial equator, close to the Milky Way, that is visible as a whole from most parts of the world and can be used to indicate the positions of many bright neighboring stars (see illustration). Five stars are of 1st magnitude or brighter; 15 are brighter than 4th magnitude. Rigel (β), Betelgeuse (α), Bellatrix (γ), and 2nd-magnitude Saiph (κ) form the distinctive quadrilateral outline inside which are the three remote 1st- and 2nd-magnitude stars of Orion's Belt, Alnilam (∊), Alnitak (ζ), and Mintaka (δ). South of the Belt is Orion's Sword, in which lies the naked-eye gaseous Orion nebula. The area contains many double stars including Rigel, several variable stars, and the dark Horsehead nebula. An immense oval ring of ionized hydrogen, Barnard's loop, surrounds most of Orion. Abbrev.: Ori; genitive form: Orionis; approx. position: RA 5.5h, dec 0°; area: 594 sq deg.
an equatorial constellation, the brightest stars of which have visual stellar magnitudes of 0.1 (Rigel), 0.3–1.2 (Betelgeuse), 1.6 (Bellatrix), 1.7, 1.8, 2.0, and 2.2. The Orion nebula, which is visible to the naked eye, is found in the constellation. The constellation has many hot stars of the early spectral types O and B; these stars form a stellar association. The best conditions for observing Orion are in the months from November to January. Orion is visible from all parts of the USSR.
in ancient Greek mythology, a giant hunter of Boeotia. According to one version of the myth, the goddess of dawn, Eos, loved Orion, and Artemis, in compliance with the will of the angered gods, slew him with an arrow. Thereupon, Orion was turned into a constellation. According to another version of the myth, Orion was turned into a constellation by Zeus for having importuned the Pleiades with his love for several years.