The Story of the Constellations in the Sky

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Constellations, asterisms, and their names. Carolyn Collins Petersen

Observing the night sky is one of the oldest pastimes in human cultures. It likely goes back to the earliest human ancestors who began to use the sky for navigation. They noticed the backdrop of stars and charted how they changed over the year. In time, they began to tell tales about them, using the familiar look of some patterns to tell of gods, goddesses, heroes, princesses, and fantastic beasts. 

Why Tell Star Tales?

In modern times, people have many options for night-time activities that compete with the free stargazing of the past. In those days (and nights), people didn't have books, movies, television, and the Web to entertain themselves. So, they told stories, and the best inspiration was what they saw in the sky. People also used the sky as a calendar, once they noticed a correlation between the stars in the sky during different times of year and the change of seasons. That led them to build observatories and temples that guided their skygazing for ritual purposes.

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Early skygazers made use of such places as Stonehenge to chart specific events tied to objects in the sky. Orion Lawlor

Viewing and storytelling were the birthplace activities of astronomy. It was a simple beginning; people noticed the stars in the sky. Then, they named the stars. They noticed patterns among the stars. They also saw objects moving across the backdrop of stars from night to night and called them "wanderers" (which became "planets").

The science of astronomy grew over the centuries as scientists figured out what the different objects in the sky are and learned more about them by studying them through telescopes and other instruments. Even today, astronomers at all levels use some of the constellations and star patterns that were seen by the ancients. For professionals, it's part of a way to "map" the sky into regions based on those constellations. For all skygazers, these constellations provide a way to roam the sky. In addition, many star names are based on ancient words, particularly from the Arabic.

The Birth of the Constellations

Besides stargazing, the ancients put the stars they saw to good use. They played cosmic "connect the dots" with the stars to create patterns that looked like animals, gods, goddesses, and heroes. Then, they created stories about these stars, which are called patterns of stars which are also known as "constellations" — or constellation outlines. The stories are the basis of many myths that have come down to us through the centuries from the Greeks, Romans, Polynesians, Asian cultures, African tribes, Native Americans, and many more. 

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A star chart showing three easy-to-spot constellations in April. Carolyn Collins Petersen

The constellation patterns and their stories date back thousands of years to the various cultures that existed in those times. For example, the constellations Ursa Major and Ursa Minor, the Big Bear and the Little Bear, have been used by different populations around the world to identify those stars since the Ice Ages. Other constellations, such as Orion, have been observed around the world and figure in the mythos of many cultures. Orion is best-known from Greek legends.

Most of the names we use today come from ancient Greece or the Middle East, a legacy of the advanced learning those cultures had. They played a huge role in navigation for people who explored the Earth's surface and oceans, as well. In addition, navigators needed and created extensive star charts to help them find their way around the planet.

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A star chart view of Alpha Centauri, with the Southern Cross for reference. Many parts of the southern sky are not visible from the northern hemisphere. Unless an observer travels south, they may never see these constellations. Carolyn Collins Petersen

There are different constellations visible from the northern and southern hemispheres. Some are visible from both. Travelers often find themselves having to learn whole new sets of constellations when they venture north or south from their home skies. 

Constellations vs. Asterisms

Most people know about the Big Dipper. It's really more of a "landmark" in the sky. Although many can recognize the Big Dipper, those seven stars are not really a constellation. They form what is what is known as an "asterism". The Big Dipper is actually part of the constellation Ursa Major. Likewise, the nearby Little Dipper is a part of Ursa Minor.

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Use the Big Dipper to help you find two other stars in the sky. Carolyn Collins Petersen

On the other hand, our "landmark" for the south, the Southern Cross is an actual constellation called Crux. Its long bar seems to point toward the actual region of the sky where Earth's south pole points (also called the South Celestial Pole). 

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A star chart showing the southern cross and a nearby star cluster. Carolyn Collins Petersen

There are 88 official constellations in the Northern and Southern Hemispheres of our sky. Depending on where people live, they can probably see more than half of them throughout the year. The best way to learn them all is to observe throughout the year and study the stars in each constellation. That makes it easier to search out deep-sky objects hidden among them. 

To figure out which constellations are up at night most observers use star charts (such as those found online at Sky&Telescope.com or Astronomy.com or in many astronomy books. Others use planetarium software such as Stellarium (Stellarium.org), or an astronomy app on their portable devices. There are many apps and programs that will help observers make useful star charts for their observing enjoyment.

Fast Facts

  • Constellations are groupings of stars into familiar-looking figures.
  • There are 88 officially recognized constellations.
  • Many cultures developed their own constellation figures.
  • Stars in constellations are not usually close to one another. Their arrangement is a trick of perspective from our point of view on Earth.

Sources

  • “International Astronomical Union.” IAU, www.iau.org/public/themes/constellations/.
  • “The 88 Constellations of the Night Sky  .” The Taurus Constellation | Learning the Night Sky, Go Astronomy, www.go-astronomy.com/constellations.htm.
  •  "What are Constellations", www.astro.wisc.edu/~dolan/constellations/extra/constellations.html.

Edited and updated by Carolyn Collins Petersen.