Early spring's lack of hazy humidity and its clear, temperate nights make it an ideal season for stargazing. Yet, for city dwellers living within a manmade galaxy of halogen headlights, mercury vapor streetlights and neon signs (insert bad Sunsphere joke here), the outer cosmos often goes unnoticed.
The stars were humanity's first signposts for global navigation. Their changing patterns throughout the year provided an accurate way to measure the seasons and endless inspiration for temple builders, storytellers, artists and scientists. Modern-day life, however, isn't quite as reverent as it used to be; in the nearly starless artificial daylight of a city night, it's easy to get stuck in a rut of earthly routines. The occasional visual tour of the heavens can serve to remind us that we are part of a much greater whole.
To obtain this sense of cosmic connection, you could grab your star charts and head out to the country for an evening beneath dark, starry skies--or you could just step out your urban back door and take a stargazing tour of the astronomical sights that are bright enough to outshine the city glow.
It helps if you move as far away from the streetlights as your yard, balcony or parking lot will allow. Or, if you're feeling really ambitious, consider taking a field trip to the World's Fair Park for an authentic lying-in-an-open-meadow, staring-up-at-the-stars experience. And don't forget to bring along your own private tour guide of the night sky, i.e. this article.
Our tour will cover the southern part of the our sky using the acronym SOAP, which stands for Sirius, Orion, Aldebaran, Pleiades, to help us remember each tour stop's name and its succession in the sky from east to west. First we need some basic tools: 1) binoculars (optional), 2) your eyes and 3) your fist.
You already know how to use your eyes and your binoculars. Here's how to turn your fist into a cosmic navigations device. When your arm is stretched out straight, the widest part of your fist covers about 10 degrees of sky. If star A is 20 degrees north of star B, to get from A to B you'll stick your arm out until it's straight, line the edge of the widest part of your fist up with star A, and then look two fist widths north to find star B.
We begin our tour as soon as the sky is fully dark, facing due south and searching a couple of first widths up from the horizon for the star Sirius, the S in SOAP. It should be easy to spot because it is the brightest star in the evening sky. Be careful not to confuse it with the planet Venus, which is brighter than Sirius and setting in the west after dusk. Keep in mind that as the night progresses, Sirius and all of the southern sky will shift west as the Earth turns. If you are starting later, say an hour after nightfall, you may need to look higher up and slightly southwest for Sirius.
From Sirius move your eyes 20 degrees or two fist widths westward, angling up toward the zenith. You will encounter a perfect line of three fairly bright and evenly spaced stars. This is the belt of the constellation Orion the Hunter, the O in our SOAP. Follow the line of the belt about two fist widths westward and you will come to our A, Aldebaran, a bright and noticeably red star.
Now move about a fist width and a half in the same line again and you'll come to our P, the Pleiades, an open star cluster that can easily be seen with the naked eye in dark skies. With your arm extended, the entire cluster can be covered with just the tip of your thumb. If you are in a brightly lit area you may need binoculars to see the Pleiades. When you connect the dots, the brightest stars in the Pleiades form a soup ladle with the handle pointing to Aldebaran.
Sirius' bright magnitude has made it an important part of many cultures' traditions throughout history. For example, the ancient Egyptians noticed that the annual first predawn rising of Sirius always preceded the Nile's flooding season. The floods brought rich soil and moisture that made civilization-sustaining agriculture possible. Thus, Sirius' rising became the starting point for the Egyptian civil calendar. Sirius resides in the constellation Canis Major, the Big Dog. Canis Major faithfully follows his master Orion the Hunter across the sky.
Largely owing to his prominent belt, Orion is one of the most recognizable constellations in the winter and early spring sky. Moving from left to right along the belt, the Arabic names for its three stars are Alnitak, Alnilam and Mintaka. Respectively these names translate to string of pearls, girdle and belt. The three stars are blue supergiants, each many times more massive than our Sun and located about 1,500 light years away.
Just under the middle star of the belt, about two finger widths to the south, is a vertical line of stars that form Orion's sword. The middle "star" in the sword is actually the brightest point of the Orion Nebula, a star-forming region full of glowing gas and hot, young stars. The nebula can be seen with the naked eye in dark skies and with binoculars in city skies.
About half a fist width up from the left side of Orion's belt is a noticeably red supergiant star called Betelgeuse. (Betelgeuse! Betelgeuse! Betelgeuse! Eh, it didn't work.) Among the known stars, it is physically one of the largest, and it may go supernova, or explode, within our lifetimes. If it were to explode today, it would become so bright that it could be seen easily in full daylight, but don't worry: It's located at a safe distance of almost 500 light years away.
Shifting westward and 60 light years out from our Sun, we come to Aldebaran, the red eye of the constellation Taurus the Bull. It is a giant star in an advanced state of evolution; its interior hydrogen fuel has been converted almost completely into helium. Its core is now powered by the fusion of helium into carbon. It is such stellar evolution that has transformed the hydrogen of the early universe in to the many diverse elements, such as carbon and iron, which make up you and me.
If you look at Aldebaran with binoculars, you will see many stars loosely clustered together in the same field of view. This is the Hyades star cluster. At a distance of only 150 light years, it is one of the closest recognizable open star clusters. The name Aldebaran comes form the Arabic word for "follower." The star was so named because it appears to follow the Pleiades across the sky.
Finally coming to the end of the SOAP string, the Pleiades is a young star cluster composed of hundreds of bright blue stars that lay roughly 425 light years from the Sun. The Pleiades were just forming while the dinosaurs walked the Earth, about 100 million years ago. The legends associated with the Pleiades are often about people who have become stars to escape some form of earthly torment. The Cherokee name for the Pleiades, for example, is Ani'tsutsã, which means "the boys." The legend holds that each bright star in Ani'tsutsã represents one of a group of boys who danced until they were lifted into the heavens to escape their parents' scolding and intentionally bad stone-soup dinner. Perhaps that's why the brightest stars in the Pleiades form a soup ladle.
In ancient Greek mythology the Pleiades are the daughters of Atlas the Titan and Pleione the beautiful Nymph. Zeus put the Pleiades in the sky to protect them from Orion's advances. When Orion died, Zeus put him in the sky behind the Pleiades. Night after night he chases them across the sky without any hope of catching them.
We have barely scratched the surface of the SOAP. Since these objects are bright, the number of legends associated with each of them is almost as numerous as generations of people who have marveled at them. Don't be afraid to follow in your ancestors' examples by making up your own star legends to help you stay connected with the cosmos. Astronomers probably aren't going to buy your argument to rename Orion after Peyton Manning, but hey, it's always worth a shot.
Suzanne Parete-Koon is an amateur astronomer and University of Tennessee physics Ph.D. candidate who studies the web of nuclear reactions that power stars and occasionally cause them blow up.