As perhaps the longest constellation the stars of Hydra the Watersnake, known in mythology as the many-headed snake that Hercules battled, meanders across the sky from east to west.
According to mythology the constellation’s great length represents the long time it took for Hercules to defeat Hydra. Hydra had nine heads, and as Hercules found out, simply cutting off each of its heads was not sufficient to slay the snake. For as soon as one head was cut off, two more would grow back in its place. So, in order to defeat Hydra, Hercules had to burn each decapitated stump. The Sun’s progression in the skies down the length of the constellation Hydra represents Hercules’ progress in killing the snake.
During northern hemisphere summer, the Sun is in Cancer the Crab as Hydra’s head rises in the East. Both Leo and Virgo stretch end to end, parallel to the snake’s body. So as the Earth revolves around the Sun, the Sun appears to move from Cancer eastward into Leo, and then into Virgo. Throughout this period, the Sun’s light drowns out more and more of the stars in Hydra and the ‘fire’ from the Sun sears the stumps as Hercules continues to successfully cut off additional heads.
Riding on the back of Hydra are two inconspicuous constellations, Corvus the Crow and Crater the Cup . These two constellations have been associated with the god Apollo. Crater has been known as Apollo’s goblet, and Corvus has been known as the bird of Apollo that sometimes performed special deeds for him.
Click here to go to the Qué tal in the Current Skies web site for more observing information.