The Big Dipper is made up of 7 prominent stars.
It is not a constellation by itself but an asterism: a recognizable pattern of stars within the larger constellation Ursa Major, or the Great Bear. Four stars form the bowl, while 3 create the curved handle, producing the familiar dipper or plough shape.
The seven stars are commonly identified as Dubhe, Merak, Phecda, Megrez, Alioth, Mizar, and Alkaid. Mizar has a visible companion called Alcor, which can make observers think the Big Dipper contains eight stars. Alcor is nearby in the sky but is not counted among the seven principal stars of the asterism.
The Big Dipper is especially useful for finding Polaris, the North Star. A line extended through Dubhe and Merak—the two stars at the outer edge of the bowl—points toward Polaris, which belongs to the Little Dipper. The Big Dipper is prominent in the Northern Hemisphere and is known as the Plough in Britain and Ireland.