The constellation of Ursa Major is the site
of a spiral galaxy known as M101. This a nearly face-on spiral
with a bright center and symmetric shape. It is located about 27
million light-years from Earth. With an estimated linear
diameter of over 170,000 light-years, this is one of the largest
disk galaxies known. M101 is a bright object with a magnitude of
7.7. It is easily visible in binoculars and small telescopes,
but an instrument larger than 4-inches is required to see any
evidence of the galaxy's faint spiral arms.
