Messier 101 The Pinwheel Galaxy
Distance: 23 Million Light Years
Size: 22 Arc Minutes
Type: Spiral Type Sc
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 900
Exposure: L 12×900 Bin 1, R 17×450 Bin 2, G 20×450 Bin2, B 30×450 Bin 2
Messier 101, also known as the Pinwheel Galaxy, is a spiral galaxy in the constellation Ursa Major. It is about 70% larger than our own galaxy with a diameter of 170,000 light years. It is estimated to contain about one trillion stars with about 100 billion of them similar to our Sun. M101 is a face on spiral galaxy, however the shape of the galaxy is asymmetrical due to gravitational interactions with other galaxies. This is apparent by the offset of the core from the center of the galaxy. M101 also contains over 3,000 HII regions which are gaseous areas illuminated by young bright stars. Most of the HII regions appear on one side of the galaxy and it is thought that the interaction with a neighboring galaxy is the reason. Messier 101 also contains many young star clusters that contain very hot blue stars. This is very apparent in the arms giving the galaxy its bluish color.
This image was captured in two nights. It is very high in the sky at sunset so I was only able to capture about 5 hours per night. I did luminance and red the first night then blue and green on the second night. The image was captured from a dark site with a SQM of 20.69. The conditions were good with clear skies, an average temperature of 60F, and humidity at 50%.