M42 the Great Orion Nebula or Orion Nebula is the prime deep sky attraction in the constellation of Orion and a showpiece object of the night sky. With an apparent magnitude of +4.0, the Orion Nebula is easily visible to the naked eye. Covering more than one degree of apparent sky it's also one of the largest of its type. The nebula is of the emission and reflection variety, a starforming region that is one of the brightest nebulae in the entire sky.