The recognizable shape of the constellation Leo the Lion makes it a great target for stargazers and its many galaxies make it attractive for observers using telescopes.
Leo the Lion is a great constellation for observers. Its shape is easy to spot in the night sky and it is one of the few constellations that looks somewhat similar to the object it is supposed to represent. Best observed in the spring, Leo rises behind Cancer the Crab. The most recognizable part of Leo is its backward question-mark shaped head. This shape is also sometimes referred to as The Sickle. To the left of the question mark is the lion's body, usually seen as a triangle.
The brightest star in Leo the Lion is the alpha star -- Regulus. Regulus makrs the period in the question mark shape. At magnitude 1.36, Regulus is a blue star lying about 77 light-years away. Regulus is sometimes considered the heart of the lion. Regulus lies very close to the ecliptic, or the plane in the sky that the sun, moon, and planets travel on. Therefore, Regulus will often make close encounters with solar system objects, even occasionally being occulted, or hidden behind, the moon.
The next brightest star in Leo the Lion is the binary star system of Algieba. Algieba lies where the neck and back of the lion meet. Algieba is a magnitude 2 star lying about 126 light-years away. The two stars in Algieba can be seen through modest telescopes. One has a yellow appearance, while the other is orange-red.
The third brightest star in Leo the Lion is the tail star named Denebola. At magnitude 2.14, Denebola lies the closest to of us of the bright stars in Regulus, at a distance of 36 light-years. Denebola is sometimes considered the second brightest star of Leo because Algieba is a two-star system.
Another star in Leo that at first appears unremarkable is one of the stars marking the lion's foot. Below the belly of the lion and just left of Regulus is Rho Leonis. Rho Leonis is an incredible 5,722 light-years away. The magnitude 3.8 Rho Leonis is one of the farthest stars you can easily see from Earth with the unaided eye. Objects farther than Rho Leonis that you can see without a telescope are galaxies, most notably, the Andromeda Galaxy.
Galaxies are popular observing targets in Leo. M65 and M66 are two galaxies close together positioned on the lion's hind leg. A third galaxy in the vicinty, NGC 3628, completes the Leo Triplet galaxy cluster. The three galaxies are all spiral galaxies. M65 is magnitude 9.3, M66 is magnitude 8.9, and NGC 3628 is magnitude 9.5. NGC 3628 is a little harder to see, being edge-on. These three galaxies all lie within one degree of each other. The Leo Triplet lies about 35 million light-years away.
Another group of three galaxies, slightly dimmer and farther apart, are M95, M96, and M105. M95 is a barred spiral galaxy at magnitude 9.69. M96 is a spiral galaxy at magnitude 9.19. M105 is an elliptical at magnitude 9.3. This trio of galaxies lies about 38 million light-years away. Many other faint galaxies lie in this area and throughout the constellation Leo.
