Corona Australis constellation. Optical image of Corona Australis, the Southern Crown. Corona Australis is a small constellation lying east of the tail of Scorpius and to the south of Sagittarius. It is an ancient grouping, one of the fifteen southern constellations listed by the great Alexandrian astronomer Ptolemy in the 2nd century AD. It has always been associated with a crown or garland in western mythology, but the ancient Chinese thought of it as a tortoise. It is sometimes referred to as Corona Austrinus