Centaurus
Centaurus, the Centaur, is a large southern constellation containing Alpha Centauri, the closest star system to the Sun at just 4.37 light-years. Alpha Centauri is actually a triple star system — the faint companion Proxima Centauri is the nearest individual star to our solar system. The constellation also hosts Omega Centauri (NGC 5139), the largest and brightest globular cluster in the Milky Way.
The Hercules family includes constellations associated with the legendary strongman and his twelve labors. It is the second-largest constellation family after Ursa Major, encompassing much of the summer sky visible from northern latitudes. Hercules himself is the fifth-largest constellation by area, though none of his stars are brighter than third magnitude — a fitting irony for such a famous figure.
Mythology & History
Heracles (Hercules in Roman tradition) was the greatest of Greek heroes, a son of Zeus known for his extraordinary strength. His twelve labors — from slaying the Nemean Lion to capturing Cerberus — are reflected in several constellations. The constellation Hercules is depicted kneeling, and its central asterism, the Keystone, represents the hero's torso. Associated constellations include Hydra (the multi-headed serpent), Sagitta (the arrow), Lyra (Orpheus's lyre, a fellow Argonaut), and Aquila (Zeus's eagle). Corona Borealis, the Northern Crown, was Ariadne's wedding crown placed in the sky by Dionysus.
Observation Tips
Hercules family constellations dominate the summer sky. The Keystone asterism in Hercules contains M13, the Great Hercules Cluster — one of the finest globular clusters in the northern sky, containing over 300,000 stars visible as a fuzzy patch to the naked eye. Lyra hosts Vega, the fifth-brightest star in the sky and a vertex of the Summer Triangle. The Ring Nebula (M57) between Beta and Gamma Lyrae is a favorite planetary nebula for amateur astronomers.