The Pinwheel Galaxy also known as Messier 101 or NGC 5457 is a face-on, counterclockwise intermediate spiral galaxy located 21 million light years from Earth in the constellation Ursa Major.

It was discovered by Pierre Méchain in 1781.

M101 is a large galaxy, with a diameter of 252,000 light-years. By comparison, the Milky Way has a diameter of 87,400 light-years. It has around a trillion stars. 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.

This image contains 100, 180 second images, 5 hours of data.
It was taken in a Bortle 4 Sky.

The equipment used was:
Celestron Edge HD 9.25
ASI ZWO240MC Pro OSC
Optilong L Extreem Filter
ZWO AM5
ASIAir Plus
Williams Optics 50mm Guide Scope
ZWO ASI 174 Mini Guide Camera.

The image was processed using Pixinsight and Photoshop.