Why Is the Big Dipper Not a Constellation?

Time lapse night sky

The Big Dipper is not a constellation because it is actually part of one. The stars that make up the Big Dipper are a part of the formal constellation Ursa Major.

Asterism vs. Constellation

An asterism is a group of stars within one or more constellations that form a pattern. The Big Dipper is classified as an asterism.

Within Ursa Major

The constellation Ursa Major has the shape of a bear. The Big Dipper makes up the bear's tail and flank.

Big Dipper

Seven stars make up the Big Dipper. The common names for these stars are Dubhe, Mizar, Alioth, Phecda, Alkaid, Merak and Megrez.

Considerations

Next to the star Mizar (in the middle of the Big Dipper's handle) there is a fainter star called Alcor.

Significance

Through time the position of the stars shift, and eventually the constellations will be unrecognizable.

References

• Merriam-Webster: asterism
• Encyclopedia Britannica: Constellation
• Big Dipper Asterism

Resources

• The Free Dictionary: Big Dipper
• Asterisms
• Ursa Major