Leo means lion in Latin and is among the twelve zodiac signs. In Greek mythology, this was the lion killed by the hero Heracles. Leo is one of those rare constellations that hold a zodiac sign under its name and also has many bright stars.  Alpha Leonis is a very bright star in the night sky (1.35 in magnitude) and is a double star divisible even in binoculars. Beta Leonis (Denebola, the lion’s tail in Arabic) is another bright star (2.2 in magnitude) of the constellation. Gamma Leonis is a binary star accompanied by a third optical component. Note that the structure of this star is different from Zeta Leonis which is an optical triple star. Iota Leonis is another binary star in the constellation which is divisible in an amateur telescope. Tau Leonis is a dimmer double star.  R Leonis is a red giant, Mira variable star, and  Wolf 359 (CN Leonis) is a flare star that periodically brightens up in the night sky. CW Leo (IRC +10216) is a carbon star that is the brightest star observed at the infrared N-band (10 μm wavelength).

Leo is also home to many bright galaxies:  Messier 65 and Messier 66 make up for the Leo Triplet along with NGC 3628, Messier 95, Messier 96, and Messier 105. Leo also owns some of the most massive structures in the universe, large quasar groups called Clowes–Campusano LQG, U1.11, U1.54, and the Huge-LQG.