Orion

Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It was named after Orion, a hunter in Greek mythology. Its brightest stars are Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), a blue-white and a red supergiant respectively. Many of the other brighter stars in the constellation are hot, blue supergiant stars. The three stars in the middle of the constellation form an unique asterism known as Orion's belt. The Orion Nebula is located south of Orion's belt. ... Orion is bordered by Taurus to the northwest, Eridanus to the southwest, Lepus to the south, Monoceros to the east, and Gemini to the northeast. ... Orion is very useful as an aid to locating other stars. By extending the line of the Belt southeastward, Sirius (α CMa) can be found; northwestward, Aldebaran (α Tau). A line eastward across the two shoulders indicates the direction of Procyon (α CMi). A line from Rigel through Betelgeuse points to Castor and Pollux (α Gem and β Gem). Additionally, Rigel is part of the Winter Circle. Sirius and Procyon, which may be located from Orion by following imaginary lines (see map), also are points in both the Winter Triangle and the Circle. ... Orion's seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars — Rigel, Betelgeuse, Bellatrix and Saiph—form a large roughly rectangular shape, in the centre of which lie the three stars of Orion's Belt — Alnitak, Alnilam and Mintaka. Descending from the 'belt' is a smaller line of three stars (the middle of which is in fact not a star but the Orion Nebula), known as the hunter's 'sword'. Many of the stars are luminous hot blue supergiants, with the stars of the belt and sword forming the Orion OB1 Association. Standing out by its red hue, Betelgeuse may nevertheless be a runaway member of the same group. [Orion (constellation). Wikipedia]