The Summer Triangle Guides Imagination Along the Milky Way
+ Von Del Chamberlain +
The stars that have become most symbolic of summertime in the northern hemisphere are known as the Summer Triangle. Three nocturnal luminaries form a large triangle that dominates our evening sky throughout the warmest months: Vega, brilliant diamond set in the ancient musical instrument of heaven, 5th brightest star of night; Altair, jeweled eye of the celestial Eagle, 11th brightest of all stars; and 19th brightest star Deneb, tail of the Swan that glides the Milky Way. These three characterize our summer months, a time to be out looking around, considering possibilities old and new, near and far.
To find the Summer Triangle, look east at dusk. High up, north of east, you will see a brilliant electric-blue star-Vega in Lyra. Down toward the horizon directly east you will find a row of three stars, the one in the middle much brighter than the others. This is Altair in Aquila. Moving to the left (north), higher than Altair but lower than Vega is Deneb in Cygnus. The three stars stand out above all others in that part of the sky, forming the great Summer Triangle.
Lyra, marked by Vega, is one of the smaller constellations of the sky, a group of stars that can be divided into a tiny triangle with parallelogram attached. Vega is the top of the little triangle. With a pair of binoculars you will notice that the star in the triangle just below Vega is actually a nice pair of stars. Lyra is the magical lyre, a tiny harp, of Orpheus, music maker of cosmic spheres, the sweetest music ever known, capable of taming wild beasts, turning Sirens into stone, changing courses of rivers and charming Olympian gods.
The other two stars belong to celestial birds. Altair marks the head of Aquila the Eagle, the Greek thunderbird, said to have carried the thunderbolts of Zeus during his war with the Titans. Deneb is the tail of Cygnus the swan. The graceful bird is laid out southward from Deneb along the Milky Way. The brightest stars can also be seen as a large cross, called the Northern Cross: Deneb is at the top of the cross; the wingspan of the swan marks the cross bar; the eye of the swan, Albireo, lies at the foot of the cross. If you have a telescope, be sure to put it on Albireo. This is one of the nicest double stars of the sky: one star is golden-yellow while the other is vivid blue.
Nestled within and near the Summer Triangle are two nice small constellations. Inside the Triangle, just north of Altair, a row of dim stars form Sagitta, the arrow. Since the arrow lies between the great birds of heaven, it can easily be imagined as having been shot at them, narrowly missing both birds. Sagitta is superimposed on a bright portion of the Milky Way.
East of the Milky Way, lower than Sagitta and just outside the Triangle, a faint patch of stars mark Delphinus, the dolphin, messenger of the sea god Poseidon. The body of the dolphin is formed by a small oval of four dim stars and another star to the south marks the dolphin's tail. This same little group was thought of as a Bow by the Skidi band of Pawnee Indians. Thus, if we are willing to mix two very different and separate cultures, we have both bow and arrow in our summer evening sky.
This week is a perfect time to go out and enjoy the stars. The Moon will be new on Thursday, leaving us with dark sky all night long. What an excellent opportunity to get into the country for one of the grandest experiences humans have ever known. When darkness comes the sky is thick with stars. Perhaps its most striking feature is the Milky Way, plunging directly through the Summer Triangle and downward to the south.
The Milky Way has been called a stellar highway, a pathway of departed souls, a dusty trail recalling a race between animals, a corn-meal path left by Coyote as he fled from a mill where he had been stealing food, a river of light and, of course, milk splashed across the sky. In reality it consists of the light of billions of stars composing the Milky Way Galaxy. It surprises most people who see it under favorable conditions on dark country nights when they notice the great amount of detail that can be seen with just their eyes. A dark rift divides it into two main portions running southward where clumps of light form star clouds. Browsing the Milky Way with binoculars or telescope is a feast for the eyes: rich clusters of stars and bright glowing clouds of gas and dust adorn this celestial thoroughfare. One can see cosmic time stretched out for study: gas clouds condensing into stars, both old and newer star clusters coasting galactic orbits; dark lanes of dust obscuring the outskirts of our home-town city of stars. All these details are missed by most people these days. How sad to live without knowing the most profound vista of all, the night sprinkled with stars, inspiration of artists and scientists from the remotest of times right up to the present.
Three stars, Vega in Lyra, Altair in Aquila, and Deneb in Cygnus can direct you onto the boulevard of heavenly light, soaring on wings of eagles and swans, powered by songs from Olympic heights, cruising the galactic expanse, boldly to go where few venture any more.