This image of M51 was taken over a period of about 4 years. My first image ever taken was of this galaxy and recently I decided to shoot it again. All data from the last 4 years, taken with a C11, Skywatcher ED80, Robtics ED110 and TEC140 were combined to get this result.
Further more rgb-data from Michael van Doorn (dutchastrocolors.com) with his Hyperstar C11, was integrated to get a nice color view.
Total exposure time was 17 hours, consisting of 110 images of 300 and 600s taken during the past 4 years.
This shows a comparison with my earlier processing:
And here is the final result: