How to Find Constellations and Major Stars
After sundown the brightest stars gradually appear. These are housed in our region of the Milky Way. Early evening is a good time to learn a few constellations – before the profusion of thousands of stars becomes apparent.
We’ll survey the constellations and major stars through four seasonal charts beginning with summer. Since Earth’s axis always points at Polaris, it is always due north at an elevation equal to your latitude, and at the end of the Little Dipper’s handle.
Polaris is the alpha star, the brightest of Ursa Minor, the Little Bear. In the chart you see the Big Dipper, part of Ursa Major, to the west of Polaris. The far edge of the Dipper points to Polaris. On the opposing side is the W-shape of Queen Cassiopeia. Since the Earth rotates once a day, all the stars turn around Polaris, so these three constellations can be used to tell the time of day, and also the time of year. The entire sky appears to rotate around Polaris once a day, and also once per year.
One concern you might have is that on the chart East is to the left, unlike on a road map. The reason is that the sky charts are meant to be viewed looking up. Hold the chart overhead with the North edge pointing north. As time advances, the counterclockwise rotation brings the Dipper down to the horizon, while Queen Cass rides higher in the sky. Most charts are drawn with evening viewing in mind and south at the bottom.
The larger dots mark the brighter stars and you can see the three dominant ones, known as the Summer Triangle, high in the sky near the zenith. The brightest is Vega in Lyra connected to a small parallelogram. The corner closest to the printed name “Lyra” is the double-double star. The Ring Nebula is found in the short southerly side of this same parallelogram. The other two Triangle stars are Altair in Aquila the Eagle, and Deneb in the long-necked Swan Cygnus – two birds that appear to fly toward one another.
Other prominent stars are Arcturus, a champagne-colored star in the west, and red Antares, literally the rival of Mars, in the south. Almost straight up is the quadrangle of Hercules with trails of stars leaving all four corners. The amazing globular cluster M13 is found along one of its sides. Not as prominent, but still important, are the stars of the Pegasus Great Square in the east, and those of the Teapot of Sagittarius in the south. You’ll note the gray band of the Milky Way seems to emanate like steam from the Teapot. This region is rich in stars, clusters, and the ghost-y nebulas.
Because we can see almost half of the sky, we can see at least two seasons in the course of a night. The lineup of Boötes, Corona, Hercules, and Lyra can be seen making their way east to west through spring and summer. The Swan, also known as the Northern Cross, can be viewed through summer and most of autumn.
Fall has fewer bright stars but plenty else to see. First, we check up on the Pole Star. Yep, still there. At times the Big Dipper dips below the horizon. Cassiopeia rides high accompanied by her King Cepheus. Cepheus strikes me as a clown king with that pointy hat of his. If you hold the chart overhead with west edge facing west, you’ll see why we call Cygnus the Northern Cross. One of the most colorful objects in the sky is Alberio at the base of the Cross. Even good binoculars reveal it as two stars of different but dazzling colors.
There is yet a rival double star in Andromeda, the maid rescued by Perseus and the Winged Horse Pegasus. She hangs onto and trails away from the northeast corner of the Great Square. If we hop two steps out on the trail, we see our neighboring galaxy M31, also called Andromeda, pictured on our menu page. Another hop out brings us to the rival double star, Gamma Andromeda. All these stars are visible with unaided eyes in a dark sky, but a small telescope is needed to see the separation and colors of the double stars mentioned.
Pleiades is an bright cluster of stars rising in the east.
I’d wait until late fall or early winter for the best views of the rest of Taurus, Orion, and Auriga.
Winter boasts a bevy of bright stars, clusters, and nebulas as does summer. To keep observing sessions brief, I do the reading and planning inside. As I bundle up, I close one eye to jump start my night vision. Orion is widely recognized as a human figure, the Hunter, and to his south and east is Sirius, the brightest star in our sky. Orion hosts many multiple stars and nebulas, all requiring telescopic aid. Betelgeuse is the red shoulder to the east, and blue Rigel is at the opposite foot. The red rival Aldebaran initiates one horn of Taurus the Bull. The Gemini twins stand over Orion, two heads, Castor and Pollux, being better than one.
Rising a little later is Leo the Lion with bright Regulus at its heart, and Denebola at the end of the tail. In one final check, we see that the Big Dipper is on the rise, bucket first. This comprises the body and tail of the much more extensive Great Bear.
I see that our spring chart has more details of the Bear. We have to look straight up to see the neck, snout, and spindly legs with three pairs of stars at the ends. These pairs are known as the Gazelle Leaps. With a good telescope, we can see a plethora of distant galaxies in and around Virgo to the south. And as promised, the spring/summer procession of Boötes, Corona, Hercules and Lyra is beginning to appear. Leo, Hercules, Boötes, and the Bear all have telescopic double stars to look for, but there is a double called Mizar at the bend of the Dipper handle that you may be able to distinguish with your own eyes.
One aspect of astronomy that has always interested me is the lore of different cultures through the ages as they tried to interpret what “the gods” were providing them up there. They saw animals, people, and objects, and devised stories that told of their relationships. The Audubon Guide and Chet Raymo’s book 365 Starry Nights are good places to start.
Images by permission from Astronomical Society of the Pacific, Bob Naeye, ed.