a Ursae Majoris


Alpha Ursae Majoris is "Dubhe", The Bear.

Dubhe forms the 'lip' of the dipper and in binoculars can be seen along with beta.
     The classic means of finding Polaris (and thereby the North Pole) is to draw a line from beta through alpha and continue it in the same direction.

The other stars in strict alphabetical order which form the famous asterism are beta, gamma, delta, zeta, and eta.

Dubhe is a second-magnitude yellow giant, 125 light years away, with a fifth-magnitude companion which orbits the primary every 44.4 years. Presently the companion is drawing away from the primary, and will achieve its maximum distance (0.84") in the years 2022-2025: orbit.

The asterism of the Big Dipper (or Plough, in the UK) is so large that binoculars can only get two stars at a time in the same field of view.

In the same field of view as beta, are two Messier objects to the southeast, best studied in medium to large telescopes. In particular the Owl Nebula (M97), one of the largest known planetary nebulae, requires a very large telescope indeed as it is only an eleventh-magnitude object with a fourteen-magnitude central star.


All files associated with The Constellations Web Page are
© 1999-2000 by Richard Dibon-Smith.