M57-the Ring Nebula-is a planetary nebula-a star slowly blowing its matter outward in a bubble-shape. The ionized oxygen gives them a characteristic Blue color. We are looking straight into the bubble so it has a "smoke ring" appearance to it. If you zoom in, you can see the central star wreaking all the havoc!

50 80-second exposures at 1600 ISO with a Optolong broadband light pollution filter
stacked with Deep Sky Stacker and post with Photoshop

Deep Sky Stacker, Photoshop