Ursa Major constellation is full of deep sky delights
Astrophotographer Mike Wiles took this image of the Pinwheel Galaxy. This spiral galaxy is a popular observing target and has an impressive diameter of around 170,000 light years — making it much larger than our own Milky Way.
Like the “Great Bear” it is meant to represent, the Ursa Major Constellation is a domineering force that rises to prominence in the Northern Hemisphere’s skies as winter fades into spring.
Encompassing a 1,280 square degree area of celestial real estate, Ursa Major is the third largest constellation and is one of the most recognizable due in large part to the Big Dipper asterism that resides within it. Like Orion’s Belt, this well-known star pattern is a key orientation point for those seeking to navigate the skies.
The Big Dipper is defined by seven stars - Dubhe, Merak, Phecda, Megrez, Alioth, Mizar and Alkaid. Observers can draw an imaginary line from Merak through Dubhe, which make up the outer edge of the Big Dipper’s “bowl” and are often referred to as the Pointers, to locate Polaris — the North Star. They can also follow an imaginary line that extends from the “handle” end of the asterism to find the showy red giant Arcturus.
Ursa Major also contains the visual companion stars Mizar and Alcor, which are sometimes called the “Horse and Rider.” These stars, which are actually multiple star systems, show up nicely in binoculars.
When it comes to deep sky offerings, the galaxy-rich Ursa Major is loaded with breathtaking targets for amateur astronomers. Two of the most popular destinations are Messier 81 or Bode’s Galaxy, which is a well-defined spiral structure that truly blossoms when viewed through a telescope; and the fainter Messier 82 or Cigar Galaxy, which is a starburst galaxy full of young stars.
Other notables include the Pinwheel Galaxy, a flashy grand design spiral galaxy that proudly displays its impressive arm structure when viewed through a telescope; and the more elusive Owl Nebula, which is a planetary nebula with a greenish hue marred by two dark voids characterized as owl eyes. The constellation also has some well-known barred spiral galaxies and a fairly-rare dwarf spiral galaxy.
Two of the most popular destinations in the galaxy-rich Ursa Major Constellation pop in this image from astrophotographer Chuck Kimball. On the left is the stunning Messier 81 or Bode’s Galaxy. On the right is the fainter Messier 82 or Cigar Galaxy.