Leo Constellation

Leo the Lion is one of the most confidently recognizable constellations in the sky, its curved row of stars forming an unmistakable backwards-question-mark shape known as the Sickle, with a bright triangle of stars trailing behind to form the lion's haunches and tail. It represents the Nemean Lion of Greek mythology, the fearsome beast with an impenetrable hide that Hercules had to defeat with his bare hands as the first of his Twelve Labors. Leo rules the spring sky with the kind of presence its name promises — anchored by Regulus, a star whose name literally means "little king."

Leo at a Glance

• AbbreviationLeo
• Genitive FormLeonis
• MeaningThe Lion
• Constellation FamilyZodiac
• Area947 sq. degrees (12th largest of 88)
• Right Ascension9h 22m – 11h 55m
• Declination-6.4° to +33.5°
• Brightest StarRegulus (magnitude 1.35)
• Best Evening ViewingApril, visible 90°N to 65°S
• Sun's Actual TransitAugust 10 – September 16 (astrology: July 23 – August 22)

Mythology and History

The Nemean Lion terrorized the region around Nemea, and its golden fur was said to be impervious to any blade, arrow, or club. Hercules, sent to kill it as the first of his Twelve Labors, eventually strangled the beast with his bare hands after discovering that weapons were useless against it, then used the lion's own claws — the only thing sharp enough to pierce its hide — to skin it. He wore the pelt as armor for the rest of his adventures, and Zeus placed the lion among the stars to commemorate the feat. Leo was one of the 48 constellations recorded by Ptolemy in the 2nd century AD, and its association with royalty and courage persisted well beyond Greece — ancient Egyptian, Mesopotamian, and Persian skywatchers all recognized a lion in roughly this same patch of stars.

Notable Stars in Leo

Regulus, the "heart" of the lion, sits almost exactly on the ecliptic — the Sun's apparent path across the sky — and is actually a system of at least four stars, though only the brightest blue-white component is visible without a telescope, roughly 79 light-years from Earth. Denebola marks the tip of the lion's tail, a white star about 36 light-years away, while Algieba, the second star in the Sickle, resolves through a small telescope into two golden-hued giant stars orbiting one another — one of the finest double-star views in the northern sky.

Deep-Sky Objects

Leo is a rewarding target for telescope owners thanks to the Leo Triplet, a group of three interacting spiral galaxies — M65, M66, and the edge-on NGC 3628 — all visible together in a single wide-field view roughly 35 million light-years away. Farther west, the trio of M95, M96, and M105 forms a second cluster of bright galaxies, making Leo one of the richer constellations in the sky for galaxy-hunting.

• Leo Triplet — a trio of interacting spiral galaxies — M65, M66, and NGC 3628 — all visible in the same wide-field telescope view, roughly 35 million light-years away
• M95, M96 & M105 — a further group of bright spiral and elliptical galaxies clustered in Leo's western half

Neighboring Constellations and How to Find It

Leo is easiest to find by locating the Sickle, a backwards question-mark of stars with Regulus at its base, high in the spring evening sky. It sits between Cancer to the west and Virgo to the east, and reaches its highest point around April, though its brightness makes it visible from nearly every populated latitude for much of the year. Leo borders Ursa Major, Leo Minor, Lynx, Cancer, Hydra, Sextans, Crater, Virgo, and Coma Berenices.

Leo is also associated with the Leonids meteor shower, visible to observers who track where these annual displays radiate from.