Canis Major, the Great Dog and Sirius

Canis Major, the Greater Dog, is a southern constellation, one of Ptolemy's forty-eight, following at the heel of Orion as one of the hunter's two hounds. It contains Sirius, the brightest star in the entire night sky, known as the Dog Star. In antiquity the heliacal rising of Sirius, its first reappearance in the dawn before the sun, marked the flooding of the Nile for the Egyptians and gave the hot dog days of summer their name. The dog is shown pursuing the hare Lepus or the hunt across the sky. In astronomical tradition the constellation is a pattern of stars rather than a zodiac sign. These are the features of Canis Major as the classical and modern traditions describe it, distinct from any astrological use; Sirius has been among the most watched of all stars across cultures.

Columba, the dove, immediately south of Canis Major, was introduced by Petrus Plancius at the end of the sixteenth century, carved from stars Ptolemy had left as an unformed patch beyond his hound's paws; its dove is usually explained as the bird Noah released from the ark, one of relatively few post-classical constellations to draw its imagery from the Bible rather than from Greek myth or from the instruments of early modern science.