So - the color may be pretty, but it's not the real thing. This image can be improved by taking many more images before combining them. I'd like to take at least 10 monochrome images to form the luminance layer and 5-10 images of each color. It would also be interesting to see just how deep and exposure I could get. The objective is to see how much additional detail in the rings could be picked up.
Color is much more exacting and tedious than monochrome, but the results appear to be interesting.
It includes several professional and amateur shots of M57 for comparison. This is contrary to the belief expressed e.g. in Kenneth Glyn Jones' book. There are even indications from investigations of deep observations such as George Jacoby's deep photos obtained at Kitt Peak National Observatory that the overall shape might be more that of a cylinder viewed along the direction of the axis than that of a ring, i.e., we are looking down a tunnel of gas ejected by a star at the end of its nuclear-burning life. The innermost region appears dark as it emits merely UV radiation, while in the inner visible ring, greenish forbidden light of ionized oxygene and nitrogene dominates the color, and in the outer region, only the red light of hydrogene can be excited. The central star was discovered by the German astronomer F. von Hahn in 1800, with a 20-foot FL reflector.