Every culture known to history and folklore has seen in the heavens distinctive patterns, called constellations, and formed by the stars. Constellations are usually consist of bright stars that appear close to each other. Oriental cultures formed complicated patterns from some of the faintest stars, creating hundreds of constellations.
"Constellation" is the name we give to seeming patterns of stars in the night sky. "Stella" is the Latin word for star and a constellation is a grouping of stars. In general, the stars in these groups are not actually close to each other in space, they just appear to be close when viewed from Earth.
Constellations are named patterns of stars. All societies created them. The classical ancient constellations that populate our sky began in the lands of the middle-east thousands of years ago, their origins largely lost to time. They passed through the hands of the ancient Greeks, who covered them with their legends and summarized them in story and verse. During Roman times they were assigned Latin names. The ancient constellations limit out only the bright patterns. From around 1600s to 1800s, astronomers invented a large group of "modern" constellations from the faint stars that rest between the classical figures, from pieces of ancient constellations, and from the stars that occupy the part of the southern sky that could not be seen from classical lands. The patterns they imagined are the constellations.
Today, it can be difficult to make out some of the shapes of the constellations because city lights obscure many of the dim stars. But they are still used as an important organizational tool to help identify and locate objects in space. Today there are currently
88 main constellations recognized by the astronomical community, but you may find different books that shows the stars connected in slightly different ways. The official constellations are specific regions of the sky, so the exact patterns are not all that important. There are some famous star patterns that use stars from only a part of a constellation, or even connect stars from different constellations.
The first thing you need to know is that constellations are not real. Constellations are imaginary things that poets, farmers and astronomers have made up over the past thousand years or so. The real purpose for the constellations is to help remind us which stars are which in the sky. On a really dark night away from city lights, you can see about a thousand to fifteen hundred stars. Trying to identify them is hard. The 88 official constellations help by breaking up the sky into more manageable sections. The constellations are mnemonics, or memory aids. The real purpose for the constellations is to help us tell which stars are which, nothing more. On a really dark night, you can see about 1000 to 1500 stars. Trying to tell which is which is hard. The constellations help by breaking up the sky into more manageable bits. Around the world, farmers know that for most crops, you plant in the spring and harvest in autumn. But in some regions, there is not much differentiation between the seasons. Since different constellations are visible at different times of the year, you can use them to tell what month it is.
On Earth, we see different constellations as we travel to different parts of the globe. The fact that some constellations were visible in the northern hemisphere and not the southern hemisphere, and vice-versa, was used more than a thousand years ago by Greek astronomers to argue that the Earth is round.
Back before people had televisions and electricity to light their homes at night, they spent a lot more time looking at the stars. People all over the world used their imaginations to draw pictures in the sky, as if it were a giant connect-the-dot game. A constellation is a chance grouping of stars. Constellations were seen by ancient people as pictures in the stars. Their origins date back hundreds of years into our past. These grouped alignments of stars, also called asterism, are known today as the constellations. Ancient cultures around the world have assigned different pictures to these star groupings. Many of the images seen by ancient people find their roots shrouded in mythology. Many of the oldest known constellations were imagined by the ancient Greek and Roman civilizations.
Since the dawn of recorded civilization, stars played a key role in religion and proved vital to navigation. Astronomy, the study of the heavens, may be the most ancient of the sciences. The invention of the telescope and the discovery of the laws of motion and gravity prompted the realization that stars were just like the sun, all obeying the same laws of physics. This study is based on the belief that each constellation has its own unique clusters of related concepts, and that the etymology of the names and associated key words will express their essential meaning.
When we look at the night sky, we see distant stars shining like faint lights. Now we know they are really brilliant lights, like the Sun, that are incredibly far away from us and from each other. Astronomers have used some wonderfully inventive methods to discover the distances to the stars, but to our eyes, they all look as if they are pinpoints of light at the same distance.
If you waited long enough, the patterns of stars you would see in the sky would change completely. The appearances of stars change as they age.
In the past, people used the constellations as markers. Some used the constellations to navigate their boats across the sea, to mark seasons of the year, or to locate special stars. Today, astronomers still use constellations as a handy marker to indicate a general area of the sky where far away celestial objects appear. Many of these extremely distant objects can be seen only with powerful telescopes.
People usually saw patterns that reflected their different cultures. Native Americans in North America imagined many animals and shapes from the natural world. The ancient Greeks found images of gods and goddesses in the stars. Sometimes people from very different parts of the world even imagined the same animal or shape in the same stars. Most of the constellations we recognize today were made up by the ancient Greeks around a thousand years ago. Different constellations are visible at different times of year, so the first appearance of these patterns told farmers of the changing seasons and reminded them to plant or harvest their crops.
The constellations also help us to find our way around the night sky and to remember which stars are which. The star names we use today are mostly from Greek and Arabic, but many are changed a bit from the original, as often happens when words are passed from one language to another. It can be difficult to picture just what those folks long ago were seeing in the stars, so don't be discouraged if you have trouble seeing their patterns. The constellations are often grouped according to the month in which they are best visible.