Bayer Designation

The system introduced by Johann Bayer in his 1603 atlas Uranometria, labelling the bright stars of each constellation with a Greek letter followed by the Latin genitive of the constellation's name — so α Orionis is Betelgeuse, even though Rigel (β Orionis) is usually the brighter of the two, a reminder that the ordering is only approximate. Roughly in order of brightness, Bayer letters remain the most familiar designations for naked-eye stars.