Blobs Leo highlights: Google earth file: Leo.kmz (8kb, kmz)
Gamma Leonis, ( Leonis ) Algeiba, lies northeastwards from eta leonis. It is a spectacular binary only 4.4 arcseconds apart with magnitudes of +2.2 and +3.5, (+1.98 integrated visual magnitude).
Constellation Leo Exposure Time 10 seconds 22:43:03 UTC, Sunday 21 May, 2006
Leo is one of the oldest and most distinctive constellations in the night sky. It lies due south around midnight in the spring. The `head` of the lion is like a backward question mark drawn by the stars; alpha, eta, gamma, zeta, mu and epsilon Leonis. The star alpha leonis, (α Leonis), Regulus, is the most prominent shining at magnitude +1.36 which makes it the 21st brightest star. The name literally means `king` and comes from the latin `rex`. Regulus lies at a distance of 69 light-years and has an absolute magnitude of -0.7, and a surface temperature of 13,000K. The star has a +7.7 dwarf companion (also a double star), 177 arcseconds away. Regulus is one of the brightest stars that can be occulted by our solar system planets. Our Moon also occults the star over two `periods` of 18 months during it`s 18.6 metonic cycle. The last series of occultations happened in September 1999; we will have to wait until 2007 before it starts again. Eta leonis lies north of Regulus and shines at magnitude +3.48. It is a type `A` supergiant, 2000 light-years away.
Many other fainter stars have been named as well, such as δ Leo (Zosma), θ Leo (Chort), κ Leo (Al Minliar al Asad ), λ Leo (Alterf), and (ο Leo (Subra). Regulus, η Leonis, and γ Leonis, together with the fainter stars ζ Leo (Adhafera), μ Leo (Ras Elased Borealis), and ε Leo (Ras Elased Australis), make up the asterism known as the Sickle. These stars represent the head and the mane of the lion.
Gamma Leonis, (γ Leonis ) Algeiba, lies northeastwards from eta leonis. It is a spectacular binary only 4.4 arcseconds apart with magnitudes of +2.2 and +3.5, (+1.98 integrated visual magnitude). The binary lies 75 light-years away and they have a orbital period of 620 years. Zeta Leonis shining at magnitude +3.44 lies 4 degrees north of gamma. It is a `F` type star nearly 50 times as luminous as our sun. Epsilon Leonis however is over 600 times solar luminosity! It is a yellow `G` type star shining at magnitude +2.98. The second brightest star,magnitude +2.14, in the constellation is Denebola. Denebola (β Leonis) makes up the tail. Denebola is a type `A3` star similar to Sirus and is only 40 light-years away. It shines with the luminosity of 20 suns. Delta with a apparent magnitude of +2.55 lies 80 light-years away. Theta lies 90 light-years away with a magnitude of +3.34 is a similar `A` type star.
R Leonis at 600 light-years away is a spectacular variable Mira-class red giant ,that ranges from a maximum magnitude of +4.4 to +11.3 over a period of 310 days. The star is found about 5 degrees west of Regulus. The cool type `M` dwarf star Wolf 359 lies only 7.78ly away. The +13.5 magnitude star is found near to 59 Leonis. The star Wolf 359, one of the nearest stars to Earth's solar system (7.78 light-years), is in Leo. Gliese 436, a faint star in Leo about 33 light years away from the Sun, is orbited by one of the smallest extrasolar planets ever found.
A former asterism representing the tuft of the lion's tail was made its own constellation by Ptolemy III in 240 B.C. It was given the name Coma Berenices.
Leo contains many bright galaxies, of which the twins (Spiral Galaxy M65, Spiral Galaxy M66) and (Spiral Galaxy M95, Spiral Galaxy M96) are the most famous.
The Leonid meteor shower is seen every year emanating from the `Sickle` around November 18th.