SkyEye

The Greek Alphabet

Johann Bayer was a celestial cartographer who compiled a star catalogue using what are now known as Bayer designations. A star's Bayer designation is a lower case Greek letter, followed by the genetive form of its parent constellation's Latin name. Under this system, the brightest star in a constellations is usually assigned the Greek letter alpha α, the next brightest star beta β and so on, but there are a number of exceptions to this rule. If there are more than 24 stars in the constellation needing a designation, lower case Latin letters (a, b, c, …, z) are used in place of lower case Greek letters. In constellations with very large number of stars, upper case Latin letters (A, B, C, …, Q) are also used. (Bayer did not use upper case letters beyond the letter Q.) Since Greek letters are not always familiar to non-scientists, a list of the alphabet is given below.

Roman Numerals

These symbols are used to designate planetary satellites and stellar luminosity classes.

Other Astronomical Symbols

These symbols were once commonly used by astronomers but these days they mostly appear in almanacs and horoscopes. The main exceptions are the symbols for the Sun and the Earth which are still often seen in published research and academic texts.

Miscellaneous Abbreviations