Science & history · Constellation guide
Leo, the lion
Leo is one of the few constellations that looks like what it is named for: a crouching lion. Six stars in the shape of a sickle outline his head and chest, with bright Regulus at the bottom.
About this picture
NASA/Goddard Space Flight Center Scientific Visualization Studio. Gaia DR2: ESA/Gaia/DPAC. Constellation figures based on those developed for the IAU by Alan MacRobert of Sky and Telescope magazine (Roger Sinnott and Rick Fienberg). NASA's page (opens in a new tab).
The map is a composite of 1.7 billion catalogued stars, not a photograph from one place: it shows stars far too faint for the eye, and no weather, Moon or city light. It is drawn here in this chart's projection, with each star where it was in 2000; the fastest-moving bright star has shifted about a minute of arc since, far less than a pixel here.
How to spot it: A sickle of six stars ending in bright Regulus. Source (opens in a new tab)
The Sickle and the little king
Six stars curve like a sickle over the lion's chest, ending in Regulus, the ‘little king’.
Ridpath (opens in a new tab) describes the head and chest outlined by six stars arranged as a sickle. At its foot, marking the lion's heart in Ptolemy's description, is Regulus, Latin for “little king”. The Babylonians knew it as LUGAL, “king”, and the Arabs as the lion's heart or the royal one.
The tail star, Denebola (opens in a new tab), takes its name from the Arabic for “the lion's tail”. The Arabs also called it by a name referring to change, the change of seasons, because of its dawn rising.
Greek writers took the figure to be the lion of Nemea (opens in a new tab), killed by Heracles as the first of his twelve labours.
Sources for this section Ian Ridpath, Star Tales: Leo (opens in a new tab)
How to find it
Leo lies on the Sun's path near the equator, so both hemispheres see it, the north on spring evenings.
By this site's calculation (opens in a new tab), Leo's middle stands about 67° up in the south at its highest from 40°N and about 38° up in the north from 35°S, and it is highest at about 9 p.m. local time in mid-April.
Regulus is magnitude 1.36 in ESA's list (opens in a new tab). The fainter stars of the Sickle and the lion's body trail behind it toward Denebola, and need a darker sky: light pollution (opens in a new tab) hides the faint stars first.
Sources for this section Bright Star Catalogue, 5th Revised Ed. (Hoffleit & Warren 1991), as computed by this site's star engine (opens in a new tab); ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab); Kat Troche (Astronomical Society of the Pacific), Check Your Sky Quality with Orion!, NASA Night Sky Network (2023) (opens in a new tab)
Galaxies and meteors
Under the lion's hind leg lie galaxies 35 million light-years away, and every November its meteors.
Messier 65 and Messier 66 (opens in a new tab), found by Charles Messier in 1780, belong to the Leo Triplet of galaxies with NGC 3628, which William Herschel found in 1784. M66 is about 35 million light-years away, magnitude 8.9, and can be spotted with a small telescope; NASA gives April as the best time.
Every November the Leonid meteor shower appears to stream out of Leo; meteor showers are named for the constellation (opens in a new tab) their meteors seem to come from. In 1833 the Leonids produced one of the great meteor storms on record.
Sources for this section NASA Hubble, Messier 66 (opens in a new tab); NASA Space Place, What Are Constellations? (updated 2022) (opens in a new tab)
Where on Earth, and when
The whole key pattern rises from anywhere north of about 70°S.
South of about 78°S, none of it rises.
North of about 78°N, the whole key pattern never sets.
Its middle climbs at least 20° high, the finder's threshold for a suggestion, from latitudes between 53°S and 87°N.
It is highest in the evening sky, at about 9 p.m. local time, in mid-April, from either hemisphere, wherever it rises. With daylight saving time, that is nearer 10 p.m. on the clock.
Worked out by this site from the Bright Star Catalogue, for a flat, clear horizon. Hills, buildings, haze and city light all cut into this; the air also lifts objects near the horizon by about half a degree. For your own place and night, use the sky finder.
Sources
- History Ian Ridpath, Star Tales: Leo (opens in a new tab) for the Sickle, the star names and the lion of Nemea · checked 27 September 2026
- Astronomy ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab) for Regulus's magnitude · checked 27 September 2026
- Astronomy Kat Troche (Astronomical Society of the Pacific), Check Your Sky Quality with Orion!, NASA Night Sky Network (2023) (opens in a new tab) for light pollution and faint stars · checked 27 September 2026
- Astronomy NASA Hubble, Messier 66 (opens in a new tab) for the Leo Triplet · checked 27 September 2026
- Astronomy NASA Space Place, What Are Constellations? (updated 2022) (opens in a new tab) for how meteor showers are named · checked 27 September 2026
- Astronomy Bright Star Catalogue, 5th Revised Ed. (Hoffleit & Warren 1991), as computed by this site's star engine (opens in a new tab) for its height from 40°N and 35°S, and best month
