Ursa Major

Third-largest constellation in the sky, in the north polar region. Its seven brightest stars make up the familiar shape or asterism of the Big Dipper or Plough. The second star of the handle of the dipper, called Mizar, has a companion star, Alcor.

Two stars forming the side of the dipper bowl further from the handle act as pointers to the north pole star, Polaris. Dubhe, one of them, is the constellation's brightest star.

Many of the stars in this constellation are moving through space at the same speed and in the same direction. Sirius and several other stars in different parts of the sky share this common motion and so belong to the ‘Ursa Major moving group’.