Constellation Leo: The Mighty Lion In The Sky
August 10 is World Lion Day – a day dedicated to raising awareness and support for the conservation of lions. It’s also a symbolic time in the sky, as the Sun enters the IAU-defined borders of the constellation Leo. What better excuse to explore this majestic star pattern? From ancient myths and dazzling stars to hidden galaxies and meteor showers, the constellation Leo has inspired skywatchers across cultures for over 6,000 years. Want to see where Leo is right now? Use the Sky Tonight app – just point your phone at the sky and follow the guide to find the lion among the stars.
Contents
- Constellation Leo facts
- Constellation Leo on the sky map
- Brightest stars in the constellation Leo
- Deep-sky objects in the constellation Leo
- Leo constellation story
- Constellation Leo: to sum up
Constellation Leo facts
- Size: 947 sq. deg.
- Right ascension: 11h
- Declination: +15°
- Visible between: 90°N – 65°S
- Brightest star: Regulus (α Leonis)
- Main stars: 13
- Messier objects: 5
- Bordering constellations: Cancer, Coma Berenices, Crater, Hydra, Leo Minor, Lynx, Sextans, Ursa Major, Virgo
Other noteworthy facts about the constellation Leo
- Leo hosts two meteor showers: the Leonids, one of the few showers known for its spectacular outbursts, and the January Leonids, a smaller, lesser-known event.
- Leo is prominent in the evening sky during the spring months in the Northern Hemisphere, so its appearance heralds the arrival of warmer weather and longer days.
- Many sources claim that the Leo constellation appears in the sky during Mufasa and Simba’s conversation in The Lion King (1994). Yet, interestingly, none of them point out exactly where.
Constellation Leo on the sky map
Spanning an area of 947 square degrees, Leo ranks as the 12th largest constellation among the 88 modern constellations recognized today. Placed along the celestial equator, Leo is classified as one of the 15 equatorial constellations. Also, Leo is a member of the zodiac – a group of constellations that the Sun, Moon, and planets appear to move through over the course of the year.
Where and when is the constellation Leo visible?
As an equatorial constellation, Leo can be seen from both hemispheres, particularly between latitudes +90° and -65°. It is best visible from March to May, with April being the prime month, as Leo reaches its highest point in the night sky, offering optimal viewing conditions.
On August 10 – the date we celebrate the Lion Day – the Sun enters the actual borders of the constellation Leo, making it a truly symbolic moment in the sky. From August 10 to September 15, the constellation Leo is obscured by the Sun and therefore invisible to observers. This is the period when the Sun actually passes through Leo, according to its true position among the stars. If astrology were based on these real-time celestial alignments, Leo would correspond to people born during this time. However, in traditional astrology, which uses a symbolic system established over 2,000 years ago, Leo represents those born between July 23 and August 22.
Where is the constellation Leo in the sky?
Leo is surrounded by a diverse set of neighboring constellations:
- To the west: Cancer, a smaller and fainter zodiac constellation
- To the northwest: Leo Minor, a lesser-known companion of Leo
- To the north: Lynx and the famous Ursa Major
- To the northeast: Coma Berenices
- To the east: Virgo, another bright zodiac constellation
- To the south and southeast: Crater and Sextans
- To the southwest: The long and sinuous Hydra, the largest constellation in the sky
Together, these constellations form a rich region for celestial navigation and deep-sky exploration, with Leo often serving as a prominent reference point due to its bright stars and distinctive outline.
How to find the constellation Leo?
Spotting Leo in the night sky is both fun and relatively easy, thanks to its distinctive shape and helpful neighboring constellations. Start by spotting the Sickle asterism – a curved line of stars resembling a backward question mark. The “dot” in this question mark is Regulus – the brightest star in the constellation, often referred to as the “Heart of the Lion.” From there, trace the body eastward to a triangle of stars ending at Denebola, Lion’s tail. You can also use the Big Dipper as a guide: draw a line down from the bowl’s end stars (Dubhe and Merak), and it will point you directly to Regulus and the Sickle below it.
How to find the constellation Leo via stargazing apps?
The easiest way to find Leo is to use stargazing apps. This way, you will not be mistaken and will identify all the stars correctly. We’ll explain how to find the constellation using the Star Walk 2 and Sky Tonight apps:
- Launch the app and tap the magnifier icon (lower-left corner in Star Walk 2 / bottom bar in Sky Tonight);
- Type “Leo” in the search bar;
- Tap the corresponding search result in Star Walk 2, or the blue target icon next to the object's name in Sky Tonight;
- You’ll see the constellation’s current position in the sky;
- Point your device at the sky and follow the arrow to find the constellation.
Need visual guidance? Watch the video tutorials on Star Walk 2 and Sky Tonight and follow the steps given there.
Brightest stars in the constellation Leo
Out of the 13 stars that form the outline of the Leo constellation, three rank among the top 100 brightest stars in the night sky.
Regulus
- Other names: Alpha Leonis, 32 Leonis, HR 3982
- Type: quadruple star system
- Magnitude: 1.4
- Name’s meaning: “prince, little king” (Latin)
- Description: Regulus is the brightest star in the constellation Leo and the 21st-brightest star in the night sky. Despite appearing as a single point of light, it is actually a star system, composed of two closely bound pairs. Located at about 79 light-years from the Sun, it lies very close to the ecliptic – the path the Sun, Moon, and planets appear to follow across the sky. Because of this position, Regulus is regularly occulted (temporarily blocked from view) by the Moon, and more rarely by planets such as Mercury and Venus. Also, it is part of an asterism known as the Spring Triangle.
Want to go deeper into the story of Leo’s brightest star? Explore our dedicated article about Regulus!
Denebola
- Other names: Beta Leonis, Deneb Aleet, β Leonis, 94 Leo, HIP 57632, HR 4534
- Type: A-type main sequence star
- Magnitude: 2.1
- Name’s meaning: “tail of the lion” (Arabic)
- Description: Denebola is a variable star located about 35 light-years from Earth, with brightness that fluctuates subtly over several hours. While it's often referred to as the second-brightest star in Leo, and it does appear that way to the naked eye, precise measurements of magnitude place it third. That’s because Algieba, a binary system, has a slightly higher combined brightness. So while Denebola is the second-brightest single star in the constellation, it comes third in total brightness and ranks 60th overall in the night sky.
Algieba
- Other names: Gamma Leonis, 41 Leo, HIP 50583
- Type: binary star system
- Magnitude: 2.0
- Name’s meaning: “the forehead” (Arabic)
- Description: Algieba is the 57th-brightest in the night sky, located approximately 130 light-years from the Sun. It’s a binary system of two red giants, renowned for its striking double-star appearance when viewed through a telescope. The combined light from both stars gives Algieba a slightly brighter magnitude than Denebola, though this isn’t always obvious to the naked eye. Interestingly, the primary star is also known to host at least one exoplanet.
Deep-sky objects in the constellation Leo
Among Leo’s many deep-sky features, we’ve chosen to spotlight several standout objects notable for their structure, uniqueness, and sheer visual charm.
Leo Triplet
- Alternative names: M66 Group, Arp 317, LGG 231
- Apparent size: 40′ x 50′ (1.5 x Moon)
- Apparent magnitude: 8.9-9.5
- Description: The Leo Triplet is a group of three interacting spiral galaxies: M65, M66, and NGC 3628 (nicknamed the Hamburger Galaxy). From Earth, they appear tilted at different angles: NGC 3628 is seen edge-on, while M65 and M66 reveal their spiral arms. The Leo Triplet is a popular target in April, when the constellation Leo dominates the sky and offers prime viewing conditions for deep-sky observers. Through binoculars, M65 and M66 may appear as faint smudges, while NGC 3628 is harder to spot; averted vision may help. To view all three galaxies clearly in one field of view, you'll need at least a small telescope.
Frosty Leo Nebula
- Alternative names: IRAS 09371+1212
- Apparent size: 25″
- Apparent magnitude: 11
- Description: The Frosty Leo Nebula is a protoplanetary nebula named for its location in the constellation Leo and its abundance of icy water grains, which give it a frosty appearance. Unusually, it formed far from the galactic plane, in a relatively clear region of space, making it easier to observe without interference from interstellar dust. As one of the nearest and brightest objects of its kind, it's among the rare preplanetary nebulae visible in amateur telescopes. While challenging to spot with small instruments, it can be observed through medium to large telescopes at high magnification.
While the Frosty Leo Nebula was named for its icy composition, many nebulae get their names from what they look like. Can you guess their names by shape alone? Take the challenge!
Owl Galaxy
- Alternative names: Smiley Face Galaxy, NGC 3758, PGC 35905
- Apparent size: 32.94″ x 29.34″ (0.02 x Moon)
- Apparent magnitude: 14.8
- Description: Nicknamed for its unique appearance, the Owl Galaxy is a spiral galaxy with two active black holes at its center. These form a pair of glowing eyes, making the galaxy resemble a smiling face or an owl’s head. The black holes are only 11,000 light-years apart, and both are active. It’s best viewed through large telescopes at high power.
Leo constellation story
Leo is one of the oldest known constellations, with roots dating back to Mesopotamia around 4000 BC. It was known as UR.GU.LA by the Babylonians, Shir or Ser by the Persians, Aryo by the Syrians, and Artan by the Turks, all meaning “lion”. Leo was also one of the 48 constellations included in Ptolemy’s Almagest – the foundational astronomical text that shaped sky mapping for centuries.
Leo has roared through the ages, but not every constellation from the ancient world still shines on today’s star maps. Think you can tell the survivors from the forgotten? Take our quiz and find out!
What is the myth behind the constellation Leo?
The constellation Leo is most often linked to the Nemean Lion, a fierce beast from Greek mythology that Heracles defeated during the first of his twelve labors. Its skin couldn’t be pierced by weapons, so Heracles strangled it with his bare hands and wore its pelt as armor. The lion was placed in the sky as a symbol of his bravery.
Another myth linked to Leo comes from the Roman tale of Pyramus and Thisbe, two lovers forbidden to be together. They planned to meet under a mulberry tree, but when Thisbe arrived, she was frightened by a lion with blood on its jaws and fled, leaving her veil behind. The lion tore the veil, leaving it blood-stained. When Pyramus found it, he thought she’d been killed and took his own life. Thisbe returned, saw what had happened, and ended her life as well. Their blood is said to have turned mulberries red, and while the lion only appears briefly, it still plays a role in Leo’s mythic associations.
Constellation Leo: to sum up
Constellation Leo is the 12th-largest constellation in the sky and shines brightest from March to May. Whether you’re tracking the Leonids, spotting Regulus near the Moon, or exploring distant galaxies like the Leo Triplet, this iconic constellation offers something for every stargazer. And whenever you're ready to explore, Sky Tonight is here to help – just point your device at the sky and let the stars guide you.
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