The Greek Alphabet and Other Symbols

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.

Lower Case Upper Case Letter   Lower Case Upper Case Letter
α Α alpha ν Ν nu
β Β beta ξ Ξ xi
γ Γ gamma ο Ο omicron
δ Δ delta π Π pi
ε Ε epsilon ρ Ρ rho
ζ Ζ zeta σ Σ sigma
η Η eta τ Τ tau
θ Θ theta υ Υ upsilon
ι Ι iota φ Φ phi
κ Κ kappa χ Χ chi
λ Λ lambda ψ Ψ psi
μ Μ mu ω Ω omega

Roman Numerals

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

Roman Arabic   Roman Arabic   Roman Arabic   Roman Arabic
1 5 9 50
2 6 10 100
3 7 11 500
4 8 12 1000

The Solar System

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

Symbol Body Symbol Body Symbol Body
Sun Mercury 1 Ceres
New Moon Venus 2 Pallas
waxing crescent Moon Earth 3 Juno
First Quarter Moon Mars 4 Vesta
Full Moon Jupiter 134340 Pluto
Last Quarter Moon Saturn
waning crescent Moon Uranus

The Zodiac

The symbols for the zodiacal constellations date from antiquity and are rarely used by astronomers.

Symbol Constellation Symbol Constellation Symbol Constellation
Aries Leo Sagittarius
Taurus Virgo Capricorn
Gemini Libra Aquarius
Cancer Scorpius Pisces

Other Symbols

Again, these symbols are rarely used by astronomers.

Symbol Meaning Symbol Meaning Symbol Meaning
Comet Descending Node Conjunction
Star Ascending Node Opposition