The Pinwheel Galaxy (also known as Messier 101) is a face-on spiral galaxy located 21 million light-years from Earth in the constellation Ursa Major (aka Big Dipper). It was discovered by Pierre Méchain in 1781 and Charles Messier included in the Messier Catalogue as one of its final entries. Since it is face on, it is rather dim to photograph (flash not allowed 😊)

M101 is a large galaxy, with a diameter of 170,000 light-years. By comparison, the Milky Way has a diameter of 87,400 light-years so about half the size. It is said to have around a trillion stars (sorry, I lost count at a half-billion). It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses. So… pretty big….

M101 has an apparent magnitude of 7.9 (human eye can see 6-7 depending on site). It can be spotted through a small telescope as just a smudge of light and is most easily observed during April.

This marks my first new capture since last December. Cold and clouds just got in the way. I did purchase a new telescope, a 9.25” Celestron with a focal length of 2350 mm (most everything else I captured was at 800mm). This represents 2.5 hours of 5-minute exposures from Friday night.