Canis Major means “the Greater Dog.” The constellation includes Sirius, the brightest star in the sky, which is also known as the Dog Star.
Cerberus was the offspring of the giant monster Typhon and Echidna, who had the head of a woman and the body of a serpent. Cerberus’s siblings were the dragon Ladon and the Hydra.
Sirius is actually two stars orbiting each other. It is so bright partly because it is only nine light years away—there aren’t many stars closer to Earth than that. It is also gradually moving closer to the Solar System.
The final of Hercules's Twelve Labors was to bring the dog Cerberus back to King Eurystheus. Cerberus guarded the gates of the Underworld, allowing people to enter, but preventing anyone from leaving. Not only did Hercules have to risk entering the Underworld, but under the conditions set by Eurystheus he wasn’t allowed to use any weapons against Cerberus. Hercules, however, was so strong that he managed to overpower Cerberus with his bare hands. Having succeeded, Hercules dragged Cerberus’s body back to Eurystheus. When the king saw the monstrous dog, he was so scared that he leapt into a giant jar.
Sirius (Dog Star), Epsilon Canis Majoris (Adhara), Delta Canis Majoris (Wezen), Beta Canis Majoris (Mirzam)
Eta Canis Majoris (Aludra), Tau Canis Majoris, Zeta Canis Majoris (Phurud), Gamma Canis Majoris (Muliphein)