Orion (constellation)

Orion is one of the largest constellations in the sky. It is supposed to look like the warrior Orion from Greek mythology. The constellation has other names in different cultures: it is mentioned under a Hebrew name in the Book of Job.

The constellation has a clear hour-glass shape with "Orion's Belt" in the centre. That part is made up of three bright stars (Alnitak, Alnilam, Mintaka) in line. The Orion constellation has 81 visible stars, including some of the brightest and most important stars in the night sky. Rigel is the brightest star in it, and Betelgeuse is a huge, rather unstable red supergiant.

The constellation includes a series of starburst nebulae where new stars are forming. The whole group of nebulae is known as the Orion complex. The complex is 1,500 to 1,600 light-years away, and hundreds of light-years across. It includes

• The Orion nebula M42
  • M43
• IC 434
  • The Horsehead nebula
• Barnard's Loop
• M78, a reflection nebula
• NGC 1999
• NGC 2175
  • NGC 2174
• Orion molecular cloud
• Flame nebula
• Train Wreck Cluster