Tonight the waxing gibbous moon shines among the stars of the constellation Cancer the Crab. Bright moonlight makes it hard to see the stars, but in the case of Cancer, there really are no bright stars to see. An old Greek myth explains why. The great hero Hercules was in a fight with the Lernean Hydra, a multi-headed swamp monster. The constellation of the hydra is well below the moon tonight. Every time Hercules cut off a head, another head would grow in its place. And all the while he was lopping off heads, something was nipping him on the heel. It was a little crab, sent by his stepmother Hera, to distract Hercules. Hercules was too busy to notice what was pinching him; he simply picked up his foot, stomped down on the hapless crustacean, and poor Cancer was crabmeat. Because the crab had bravely attacked Hercules, Hera rewarded him by making him a constellation. But because he had failed, she made the stars of Cancer very faint.