Messier 109
Beautiful barred spiral galaxy M109, 109th entry in
Charles Messier's famous catalog of bright Nebulae and Star
Clusters, is found just below the
Big Dipper's bowl in the northern constellation Ursa Major.
In telescopic views, its
striking central bar gives the galaxy the appearance of the Greek letter
"theta", θ, a common mathematical symbol representing an angle.
Of course M109 spans a
very small angle in
planet Earth's sky, about 7 arcminutes or 0.12 degrees. But that small angle corresponds
to an enormous 120,000 light-year diameter at the galaxy's estimated
60 million light-year distance.
The brightest member of
the now recognized Ursa
Major galaxy cluster, M109 (aka NGC 3992) is joined by three spiky foreground stars
strung out across this frame.
