Spiral galaxy in Triangulum
Also called the Pinwheel Galaxy, Messier 33 is the second-closest spiral galaxy to us after the famous Andromeda Galaxy. Like the Andromeda Galaxy, it can be seen with the naked eye, but with an overall magnitude of 5.7, it is a more difficult target and requires very dark skies. It is estimated to be 2.3 million light years away, which is just a bit further than the Andromeda Galaxy. The Triangulum Galaxy is therefore the most distant object that can be seen without optical aid (at least by most people).
Through a telescope, Messier 33 is
not very impressive at first sight, because its low surface brightness makes it
difficult to see well. However,
with patience and good observing techniques, quite a few details in the
galaxy’s structure can be discerned.
Image details: Exposure times of 33 minutes luminance and 36 minutes each of red, green, and blue, taken with an SBIG ST-8300M camera through a Meade 12” telescope at f/5.6.