Flamsteed and Bayer
Stars are designated by names, letters, and/or numbers. For example, the brightest star in the zodiac is in the constellation Taurus and has the proper name Aldebaran. This name derives from an Arabic phrase meaning “the follower” because it rises after the bright star cluster The Pleiades. It is also known as Alpha Tauri. The alpha comes from the 1603 star atlas of the German astronomer Johann Bayer. He ordered the stars in each constellation with Greek letters. Alpha usually indicates the brightest star, but there are many exceptions. Tauri is the genitive case of the constellation name. Aldebaran is also called 87 Tau from the 1725 star catalog by the English astronomer John Flamsteed. He allocated numbers from west to east in each constellation with help from later astronomers.
Other Variations on Naming
Usually only brighter stars have proper names and dimmer stars have Greek letters or Flamsteed numbers. Variable stars sometimes have capital Roman letters, such as TX in Pisces. Rarely, stars are cataloged in other ways, for example 999 in Aries comes from the Yale Bright Star catalog. Stars located close to each other sometimes are given Greek letters with superscript numbers, for example Omega1 and Omega2 in the Scorpion.