Jimmy Westlake's Celestial News column appears monthly in the Steamboat Today.
Find more columns by Westlake here.
What's that bright star rising in the northeastern sky as darkness falls this month? It's the star Vega, and its arrival is a sure sign that summer is just around the corner.
Speaking of corners, Vega marks one corner of the well-known asterism called the Summer Triangle and is the first corner of the triangle to pop up above the horizon.
Vega is the alpha star in the constellation named Lyra the Harp. The name Vega translates into "the plunging vulture," so named because it marks the head of a vulture holding the heavenly harp in his beak. Lyra represents the harp made from an empty tortoise shell by the famous mythological musician Orpheus. In addition to the flashy star Vega, this constellation includes a small but distinctive parallelogram of four stars that represents the strings of the harp and dangles below Vega as it rises in the northeastern sky after dusk.
Lyra is a tiny, compact constellation and is easy to identify, primarily because of Vega. Astronomers have determined that Vega rotates with its axis pointed almost directly at the Earth and sun, which means that our sun might be the pole star as seen from some Vegan planet, just as Polaris happens to be the North Star for Earth.
Brilliant Vega might be Lyra's main claim to fame, but there are many others.
The star marking the bottom right corner of the parallelogram is an unusual binary star named Sheliak. By chance alignment, once every 13 days, Sheliak's fainter star eclipses its brighter star, causing it to suddenly drop to one-half its normal brightness. Sheliak is one of the finest eclipsing binaries in the sky, and its variations in light can be followed with the unaided eye.
Not far from Sheliak is the famous Ring Nebula, also known by its catalogue number, Messier 57, or M57 for short. Often pictured in textbooks as the best example of a planetary nebula, the Ring Nebula was formed when a dying red giant star blew away its outer layers. The shells of gas continue to expand away from the star, forming what looks like a ghostly little smoke ring in the sky. A small telescope is required to spot the Ring Nebula, and its exact location can be found on any good star chart.
Right beside Vega is the famous "double-double" star, Epsilon Lyrae. A keen eye can manage to split the two main stars, but a telescope reveals that each of those again is double.
There's a lot to see and enjoy in this tiny constellation of summer, Lyra, Heaven's Harp.
Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published all around the world. Visit his Web site at www.jwestlake.com.