M-51 the Whirlpool Galaxy
M-51 is a face-on spiral Galaxy which is caught up in a gravitational interaction with the smaller companion galaxy NGC 5195. It is without doubt one of the most famous galaxies in the sky. They both have bright cores which are easily seen in telescopes of modest size. Hints of the spiral structure can be seen visually with 8-10" scopes. Many red emission regions are seen throughout the arms in this photo. Also visible are the smaller galaxies IC 4278 directly below the core of NGC 5195, and the edge-on IC 4277 which is about 8 o'clock from the core of NGC 5195.
This image is a composite of 180 minute and 150 minute exposures taken on hypered Kodak PJ400 film at f/10 and 3100mm FL via 1.4x telextender, and a single hypered Kodak Technical Pan film exposure of 60 min at f/7 and 2200mm FL. Photographic instrument was a 12.5" f/7 Newtonian.