When you look up at the stars, does it sometimes seem to you that you can trace out squares, letters, and other familiar figures? In nearly all parts of the world, people of long ago Aid this, too. As they observed groups of stars, they gave them names.

It is not always easy to make out in the sky the figures that suggested the names. So don’t expect the constellations to actually have the outlines that the names suggest.

The Greek astronomers listed 48 constellations, and 40 more have been named since their time, so that we have constellations the sky.

Of course, not all of the constellations can be seen from any one place on earth. Some are in the skies of the Southern Hemisphere; some can be seen only south of the equator.

As the earth travels around the sun, new star groups appear above the horizon. The circumpolar constellations, which seem to wheel around the North Star, stay in sight act year. In addition, there are constellations that appear only in the winter, spring, summer, or autumn.