Constellations are like countries on a wall map. They help narrow down the search for those tiny hard-to-find little cities or deep sky objects you would like to visit. By learning the constellations, you also share in the imagination of the people who created them thousands of years ago. Today there are 88 internationally recognized constellations. From either hemisphere, forty-five to fifty should be visible throughout the year.
Most northern constellation names come from the Greeks and Romans, who had vivid imaginations and no television to watch at night. They depicted the lives of the gods and goddeses, heroes and monsters that made up their legends. The southern constellations were mostly named during the seventeenth century by European astronomers who gave them mundane names like the Microscope, the Telescope, and the Sextant.
Expanding Your Horizons
Not all the constellations look like what they’re supposed to, and there are so many of them, it’s tough to keep them all straight.
First, get a good star chart. A revolving star wheel, called a planisphere, is an excellent choice. When you set it for the current time and date, it shows what stars and constellations are visible from your location right then. Monthly star charts that appear in astronomy magazines also work well. Use a flashlight that emits red-colored light to read your star chart. Red light works best because it does not spoil your night vision like white light does. Stay away from porch and street lights too.
The next step is to decide just what constellations you want to tackle. On any given evening, set your sights on mastering no more than four new star figures. Carefully trace them in the sky as you learn them and then go back and review the ones you found earlier. On your next night out, before you push off again into uncharted waters, go over what you memorized the previous night.
Studying the constellations over a period of a few hours also serves as a dramatic reminder that the Earth is spinning in space. Constellations near the equator rise and set while those near the North or South poles always seem to be hanging around in the sky. The circumpolar constellations located near the North Celestial Pole include some very famous star groups such as the Big Dipper, the Little Dipper, and Cassiopeia.
What’s Your Sign?
When pointing out constellations to someone else, be prepared for someone to ask the big question. "Can you show me my astrological sign?"
Twelve constellations make up the signs of the Zodiac. The reason these particular star groups were chosen is because they form the "Highway of the Gods." If you point your arm to the east where the Sun or Moon came up and move it across the sky to where it set, you have just traced out the ecliptic, or the pathway where all the major members of our solar system can be found. The early Greeks and Babylonians thought the planets, the Sun, and Moon were gods walking across the sky. They also recognized that the constellations visited by these gods must be very special. That is why these twelve particular constellations were chosen.
Incidentally, there is a lot of confusion when people go out on their birthdays and try to locate their sign in the night sky. When the ancients put this whole thing together they reasoned that the constellations must be at their greatest importance when the King of the Gods, the Sun, was visiting them. So, on your birthday, you will not find your sign in the nighttime sky. It is straight overhead at 12 noon right behind the Sun. Unless you are blessed at that very moment with a total solar eclipse (when some stars are briefly visible in the daytime), you will have to wait six months before your special constellation rolls around to the nighttime sky.
Capturing the Constellations on Film
Putting together your own personal set of constellation photos is fast and easy. All you need is
1) a 35mm camera capable of time exposures
2) a 50mm or 55mm lens
3) a steady tripod
4) a shutter release cable (with lock)
5) slide or print film (ISO 400 to 1000)
To create your own set of constellation photos, first set your lens at f/2.8 to prevent stars from looking like footballs around the edges of your photograph. Set your focus at infinity. Then frame the constellation in the camera finder, and open the shutter for about 20 seconds. Exposures longer than 20 seconds will begin to record the rotational movement of the Earth, and the stars will "trail" on the film instead of appearing as nice sharp points. You will be amazed at the sheer number and different colors of stars visible in the photographs that were invisible to your eyes alone.