Abbreviation: Leo

Genitive: Leonis

English: The Lion

Size Ranking: 12th

Area: 947 square degrees.


This large impressive constellation,  is one of the few constellations that looks like the figure it is meant to represent, in this case, a crouching lion, albeit, from our point of view, upside down. The Lion’s head is outlined by the so-called Sickle of six stars from εLeo to αLeo; the Lion’s body stretches out behind, its tail marked by βLeo. Mythologically, this is the Lion reputedly slain by Hercules as the first of this 12 labours. Leo is a constellation of the Zodiac, lying between Cancer and Virgo. The Sun passes through it from mid August to mid September.


Features of Interest:

The Sickle is an easily recognizable pattern of six stars, shaped like a inversed reversed question mark or a hook. It consists of the stars ε, μ, ζ, γ, η and αLeo.

αLeo, named Regulus, ‘the little king’, is the faintest of the first magnitude stars, magnitude 1.4. It is a blue-white star 77ly away and has a wide 7.7 magnitude companion, separation 177”, PA 307°.

βLeo, named Denebola, ‘the lion’s tail’,  is a blue-white star 36ly distant, magnitude 2.1.

γLeo, named Algieba, ‘the forehead’, consists of a pair of golden-yellow giant stars of magnitudes 2.3 and 3.6, sep. 4.3”, PA 124°, orbiting in about 600 yrs. They are 126ly away. They are considered to form an exceptionally handsome double, one of the finest in the sky.

δLeo, named Zosma, magnitude 2.6, is a blue-white star, 58ly distant.

εLeo, named Asad Australis, is a yellow giant 251ly away and magnitude 3.0.

ζLeo, named Adhafera, at magnitude 3.4, is a giant white star 260ly away.

ηLeo, is a white star of magnitude 3.5 and 1826ly distant.

θLeo, named Chort, is 76ly away, and is a 3.4 magnitude white star.

μLeo, named Rassalas also known as Ras Elased Borealis, is an orange star 179ly distant, and magnitude 3.9.



1. Redshift 2 – Maris Multimedia

2. The Guiness Book of Astronomy – Patrick Moore

3. Stars and Planets – Ian Ridpath and Wil Tirion

4. Sky Charts – Cartes du Ciel V 2.75.