Summer’s Brightest Stars
Three points to summer’s triangle
Thursday’s full moon brightens the sky from dusk till dawn. American Indians called this the sturgeon moon, as it marks the time when these great fish once began their migration and were most easily caught. Sturgeon have been plying our waters for more than 150 million years, yet today most species are endangered.
More common names for August’s full are the grain moon, the lightning moon, the green corn moon and the red moon.
As darkness settles, Vega the harp star, one of the brightest stars of summer and the fifth-brightest overall, shines almost directly overhead. Golden Arcturus, far to the west, is the only visible star brighter. Vega marks the western-most point of the Summer Triangle, with Deneb in Cygnus and Altair in Aquila the other two point in this stellar asterism.
Shining a dazzling blue-white, Vega is one of the closest stars to Earth at about 25 light-years distance. It is roughly two and a half times the size of our sun and burns twice as hot, producing far more energy than the sun and racing through its first-stage hydrogen fuel. At 500,000 years old, Vega is one-tenth as old as our sun, yet already this star is halfway through its lifespan.
About 20 degrees to the northeast of Vega is Deneb, the 19th-brightest star in our sky. The star’s name translates from Arabic to mean tail, which is what it marks in the constellation Cygnus the swan. Looked at with Deneb at the top, these same stars become the Northern Cross. A class-A super-giant, Deneb is a beast, shining more than 150,000 times brighter than our sun.
The last stop in the Summer Triangle is Altair, the 13th brightest star in the sky. Loosely meaning the flying eagle in Arabic, Altair is the alpha star in Aquila the eagle, its wing tips marked by the stars Alshain and Tarazed to either side.