Constellation Leo (Lion)

Leo: IAU Constellation Map [150]


Leo is a conspicuous spring constellation and you can easily recognize in the stars a lying lion with its head held high or an upright lion with its head stretched out - depending on how you connect the stars. Others see in the figure a shrew with its head where the lion's rear part is and the upwardly stretched, curved tail where the lion's head is. But there is also a certain resemblance to an iron, and the western part of the star alignment resembles a sickle. [67] The brightest star, Regulus, is close to the ecliptic and so sometimes beautiful conjunctions with planets or the moon occur there. The area of the constellation is 947 square degrees and the center culminates around March 1st. [9, 15]

Stars with Proper Names [154]
α Leo Regulus, Cor Leonis, Rex, Al Kalb Al Asad, Kabeleced
β Leo Denebola, Deneb Aleet
γ1 Leo Algieba, Algeiba, Al Gieba
δ Leo Zosma, Zozma, Zosca, Zozca, Duhr, Dhur, Zubra
ε Leo Ras Elased Australis, Al Ras Al Asad Al Janubiyyah, Algenubi
ζ Leo Adhafera, Aldhafara, Aldhafera
θ Leo Chort, Coxa, Chertan
κ Leo Al Minliar Al Asad
λ Leo Alterf
μ Leo Ras Elased Borealis, Rasalas, Ras Al Asad Al Shamaliyy, Alshemali
ο Leo Subra
Data for constellation Leo [150]
IAU NameLeo
IAU GenitiveLeonis
IAU Abbr.Leo
English NameLion
Opposition27 February
Season (47° N)November … May
Right Ascension09h 21m 37s … 11h 58m 26s
Declination-06° 41' 30" … +32° 58' 09"
Area947 deg2
Neighbours (N↻)LMi, Lyn, Cnc, Hya, Sex, Crt, Vir, Com, UMa

Deep-Sky Object Descriptions


Mythology and History

It is very likely that this is the lion from the Herakles saga, which he mastered in his first task, which Eurysteus asked him to do.

Constellation Leo
Constellation Leo: Illustration from «Uranometria» by Johann Bayer, copper engraving by Alexander Mair, 1603 [28]

The lovely landscape of Nemea lies on the southern Greek peninsula of Peloponnese. A particularly dangerous beast lived there: a lion with a skin hard as steel, yet supple. His terrible claws sharp and hard as diamond. This lion was also not easy to catch and kill, because it lived in a cave with two escape routes. Heracles' arrows could not hurt him and all his weapons failed. In order to prevent the lion from escaping, Heracles blocked the second escape route of the cave and, penetrating from the front, he finally strangled him with his bare hands. His knife could not even penetrate the dead lion's body and so he had to use the diamond-hard claws to peel off the lion's fur. Heracles put his skin over his shoulders and wore it like armor.

The lion was the son of Echidne and Orthos. Echidne was a beautiful woman, but only halfway; from there her body continued as a spotty snake. Orthos was Echidnes fathered with Typhon and was a dog with two heads. The lion's sister is the famous Sphinx.

The lion as a constellation is therefore also called Nemean Leo, Nemeaeus, Nemeaeum Monstrum and Hercules Leo. In Persia it is called Ser or Shir, in Turkey Artan, in Syria Aryo and in Babylonia Aru; this word always means a lion. In the attempt to Christianize he was changed into Daniel's lion or - ridiculous as it may sound - into the unbelieving Thomas. [20, 67]


  • [9] «Drehbare Sternkarte SIRIUS» von H. Suter-Haug; Hallwag-Verlag, Bern
  • [15] «Hartung's Astronomical Objects for Southern Telescopes» by David Malin and David J. Frew; Melbourne University Press 1995; ISBN 0-522-84553-3
  • [20] «Sternbilder und ihre Mythen» von Gerhard Fasching; Zweite, verbesserte Auflage; Springer Verlag Wien, New York; ISBN 3-211-82552-5 (Wien); ISBN 0-387-82552-5 (New York)
  • [28] «Uranometria omnium asterismorum continens schemata, nova methodo delineata aereis laminis expressa» Johann Bayer, Augsburg, 1603; DOI:10.3931/e-rara-309
  • [67] The Starry Sky: Leo by Deborah Byrd; Astronomy 3/94, p.51
  • [150] IAU: The Constellations, 11. Oktober 2020;
  • [154] Yale Bright Star Catalog, 15. Oktober 2020;