Leo. The constellation of Leo (The Lion). This constellation lies on the plane of the ecliptic; the brightest object seen here is the planet Jupiter. The components of the constellation are a 'sickle' or back-to-front question mark at right with the star Regulus (alpha-Leonis) at its base and a triangle of stars above and to the left of Jupiter at the eastern end of Leo. Gamma-Leonis is a beautiful double star (binary star) with a period of 617 years. It is seen here almost directly above Jupiter.