Two Birds and a Harp

Last week we talked about the brightest stars in the summer skies - the first stars you can see as the sky begins to darken. Vega, the 5th brightest star in the sky, a blue-white star, is one of the stars in the Summer Triangle. Now that you know how to spot Vega, you can easily use the Summer Triangle to find three summer constellations. 

After the Sun sets, look toward the East. Near the zenith of the sky, you will see Vega shining brightly. If you take a little more time to look, I bet you will be able to find two other bright stars that, with Vega, form a large triangle. This asterism, or familiar star shape that is not an official constellation, is known as the Summer Triangle. See star chart below, set for Peoria at 10 PM. 

Click for larger image. Look high in the East at 10 PM to see the summer triangle. Image Credit: Stellarium.

Vega is the brightest of the stars in the Summer Triangle, and the brightest star in the small constellation of Lyra the Harp. According to Greek mythology, Lyra represents the lyre of Orpheus, the great musician. He used his lyre to charm rocks, streams and trees with the magic of his song. He even used it to try to bring his young wife Eurydice back from the underworld, a tragic story you can read about here. 

Lyra is often represented as a bird behind a harp or lyre. The name Vega comes from the Arabic word al-nasr al-waqi’ that can mean either the swooping eagle, or the vulture. Image credit: Johannes Hevelius' atlas of constellation images, Firmamentum Sobiescianum sive Uranographia.

At the most southern point of the triangle is Altair, the 12th brightest star in the sky and the second brightest in the triangle. It is the closest star you can see in the sky tonight, only 16.5 light years away!  Altair is the brightest star in the constellation of Aquila the Eagle, the thunderbird of Greek mythology. Zeus' bird, Aquila would carry and retrieve the thunderbolts which the mercurial god would hurl at his enemies.

Aquila as depicted in John Flamsteed's Atlas Coelestis first published in 1729. Image credit: Wikipedia Commons.

Deneb is the dimmest of the triangle stars, but still a bright star - the 19th brightest in the night sky. Deneb is toward the East, and lower in the sky then Vega. It is a blue-white supergiant (super big and super hot!) and is very far away. It is about 200,000 times more luminous than our Sun, but does not appear excessively bright in our sky because it is approximately 2,600 light years away! Deneb, an Arabic word that means tail, is the brightest star in Cygnus the Swan. There are several Greek myths associated with the swan in the sky, which usually represents Zeus. In one tale, Zeus took the form of a swan and  seduced Leda on the banks of a river. Leda later gave birth to an egg, out of which Castor and Pollux hatched (the Gemini twins) and Helen, the beauty of Troy. 

Cygnus the Swan, as represented in Firmamentum Sobiescianum sive Uranographia.

The swan is easy to spot, even in city lights. The long neck and body of the swan are crossed by a line of stars representing Cygnus' wings. Find it in the sky, and you will easily see why it is also called the Northern Cross.

Of course the stories I have shared about these constellations are just one version of the legends, and from one culture's point of view. People from all over the world see different shapes and stories in the sky, depending on which legends are important to their worldview.  

Next time you are outside at night, look up! There are all sorts of stories and legends in the night sky. Visit us at the Dome Planetarium at the Peoria Riverfront Museum to learn more about constellations and the legends they represent.