The Big Dipper is an asterism, which means a recognizable pattern of stars, within the constellation of Ursa Major. Ursa Major is one of the 88 constellations recognized by the International Astronomical Union (IAU). It is best known for containing the Big Dipper, which forms the shape of a ladle or plow.

The Big Dipper is formed by the seven brightest stars in Ursa Major. These stars are:

* Alkaid (η UMa)

* Mizar (ζ UMa)

* Alcor (80 UMa)

* Megrez (δ UMa)

* Phecda (γ UMa)

* Merak (β UMa)

* Dubhe (α UMa)

The Big Dipper is located in the northern hemisphere and can be seen throughout the year from most locations in the world. It is most visible in the spring and summer months when it reaches its highest point in the sky.

Ursa Major is a much larger constellation than the Big Dipper. It is the third largest constellation in the sky, covering an area of 1280 square degrees. Ursa Major contains many other notable stars and galaxies, including:

* M81, a spiral galaxy

* M82, a starburst galaxy

* M101, a spiral galaxy

* M108, a barred spiral galaxy

The Big Dipper is a useful tool for navigating the night sky. By following the curve of the Dipper's handle, you can find Polaris, the North Star. Polaris is located at the end of the Dipper's handle and it always points to the true north.