Centaurus and Crux constellations. These are bright constellations in the southern hemisphere, representing a centaur and the Southern Cross respectively. The brightest star in Centaurus is Alpha Centauri (left one of the two bright stars at lower left). To the naked eye this is the third brightest star in the night sky, but it is in fact a close binary star, whose brightest member alone is only the fourth brightest star in the sky. Just right of lower centre is Crux, formed of four bright stars in the shape of a cross. Just below and left of Crux, there is a dark patch silhouetted against the bright Milky Way. This is a foreground dust cloud called the Coal Sack.