Search the sky for Draco the Dragon
Published 7:10 pm Thursday, September 2, 2010
Watching the stars on these mild September evenings is such a relaxing way to unwind after a long day.
One of the great summer constellations has been unwound for a long time. The constellation Draco is supposed to be a dragon in the sky, but it looks more like a coiled snake because, according to Greek and Roman mythology, Draco got stretched out in the line of duty.
Locating Draco the Dragon is not an easy task if you’re new to constellation hunting. To quote the great Beatles’ classic, it takes a long and winding road in the northwestern evening sky.
With the help of the bright Summer Triangle neighboring constellations that it winds around you can spot this challenging celestial dragon.
You may want to pull up the September star map from last week’s column or go to www.lynchandthestars.com to find the great beast. In a way it looks like a backward S. It should be dark enough by about 9 p.m.
Look nearly overhead for the brightest star you can see. That will be the star Vega, the brightest star in Lyra the Harp, and the brightest star in the famous Summer Triangle.
Look about 10 degrees below Vega in the direction of the northern horizon for the small but distinct lopsided diamond of stars that outline Draco’s head. Ten degrees is about the width of your fist held at arm’s length against the sky.
From Draco’s head look about 15 degrees to the lower right for two more fainter stars. The line from Draco’s head to those two stars makes up the neck of the stretched-out dragon. From there the body of Draco kinks off to the left in a nearly straight line of brighter stars about 20 degrees long. The tail of the dragon becomes a nearly vertical line from there and ends right between the cup sections of the Big and Little Dippers.
Astronomically, the most significant star in Draco is Thuban, found toward the end of the Dragon’s tail. Thuban used to be the North Star about 3000 B.C. Presently the star Polaris, at the end of the handle of the Little Dipper, is within 2 degrees of the North Celestial Pole, which is a projection on the sky of Earth’s North Pole. In other words if you were standing at the North Pole, the North Star will be directly overhead.
The Earth’s axis has a super-slow wobble that takes 26,000 years to complete one cycle. About 3000 B.C. the northern end of the Earth’s axis was pointing at Thuban. Now it’s directed toward Polaris, and in the year A.D. 21,000 the Earth’s axis will be pointing at Thuban again. You probably don’t want to wait up for that.
So how did Draco the Dragon wind up unwound in the celestial dome? Hera, the queen of the gods of Mount Olympus, was given a beautiful set of solid gold apples as a wedding present from her new husband, Zeus, the king of the gods. Hera had her pet dragon Draco guard the apples.
Hera knew the royal marriage would fall apart, and when it was all over the golden apples would still be hers. Draco guarded those apples 24/7 and fended off many thieves, including Zeus when the marriage collapsed.
One lonely, moonless night while Draco was snoozing at his post, Hercules, the legendary Greek hero, smashed the palace gate and leaped toward the golden fruit. Draco roused himself immediately and a titanic battle broke out that went on for hours.
Hercules managed to pull a dagger out of his shoe and pierce it right through the beast’s heart, and Hercules made off with the golden apples.
Hera, upset about losing her lifelong pet, rewarded Draco for his loyalty by magically placing his body in the stars as an eternal honor.
The early Christian church saw the constellation as the snake that tempted Adam and Eve to eat the forbidden fruit in the Garden of Eden. To them, Draco represented original sin.
Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Washington Starwatch,” available at bookstores. Check his website, www.lynchandthestars.com.
The Everett Astronomical Society: www.everettastro.org/.
