As kids, the Big Dipper is usually the first pattern of stars we learn to pick out in the sky. But the Big Dipper is not a constellation. The Big Dipper is just a portion of the constellation known as Ursa Major the Great Bear. The astronomical term for any star pattern that is not a constellation is “asterism”. Asterisms can be like the Big Dipper, where they are formed from a portion of a constellation, or they can be stars from multiple constellations.
The Big Dipper is the part of the Great Bear that forms the back half of his torso and his abnormally long tail. Look in front of the bowl of the Big Dipper to find the rest of the bear’s body and his triangle head. The legs can also be found extending below the body.
Another famous asterism visible in the evening sky at the moment is the Sickle. The Sickle’s curved shape makes it look distinctly like a backward question mark, and it marks the head of Leo the Lion. This weekend, the Sickle can be found in the east after sunset. The brightest star of the Sickle is Regulus at magnitude 1.4. It marks the point at the bottom of the question mark. Rising behind the Sickle is the rest of Leo the Lion’s body, which is formed by three stars in a triangle.
Some other asterisms are
- The Summer Triangle
- The Winter Hexagon
- The Great Square of Pegasus
- The Northern Cross
- The Teapot
- The Coathanger
Learn more details about some popular asterisms and what time of year they can be spotted.
-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.