Bayer Designation - Revised Bayer Designations

Revised Bayer Designations

Some stars were "border stars", falling on the boundaries between two constellations, and Bayer would assign them a Greek letter from each constellation. The two most prominent examples are β Tau/γ Aur, and α And/δ Peg. When the International Astronomical Union (IAU) outlined the official 88 constellations with definite boundaries in 1930, it declared that stars and other celestial objects can be assigned to only one constellation. Consequently, the redundant Bayer designations for those two stars were scrapped, and now only Beta Tauri and Alpha Andromedae are used. Another star, σ Lib, was formerly known as γ Sco, though it is well inside Libra. A few stars still do not lie (according to the modern constellation boundaries) within the constellation for which they are named. Nonetheless, these designations have proved useful and are widely used today.