M57 the Ring Nebula

The famous ring nebula, M57, is a classic example of a planetary nebula. It is a showpiece telescopic object in the northern hemisphere's summer sky. The phrase "planetary nebula" is an old description for these type objects. However, by the 1930's astronomers began to realize they have nothing to do with planets. When first observed, they did look a bit like planets, but a bit nebulous. That's when they began to be called planetary nebula, a descriptive name which persists to this day. The classic Ring Nebula is an object  large enough and bright enough to be plainly visible with a fairly modest scope (3" aperture and up) and about 50x power. When you see it, it appears strikingly three dimensional; seemingly hovering like a cosmic smoke ring somewhere between us and the celestial  background. In fact, planetary nebula are smoke rings of the cosmic or stellar sort. They are created when a star reaches the end of it's life cycle and begins to blow off its outer layers. Deep in its core the dying star starts to fuse together the helium and formed during its earlier days. The heat and violence of that nuclear fusion blows away its outer layers, which we see as the smoke ring, or ring nebula. What remains is uncovered white hot core of the former star. It is plainly visible in the center of this image. That white hot dwarf star is only about as big around as our earth, but it is so hot that it glows and radiates with a brightness and intesity of 20 of our suns. It will take billions of years to cool down to the 5000 degrees of our sun. But since there are no more nuclear processes going on, it eventually will cool down and finally end up a cold dark cinder.But. for now, the intense radiation emanating from that stellar core is what is lighting up and continuing to blow away its ring nebula.

10" F6.3 Schmidt Cassegrain Telescope, Modified Canon 300D, Prime Focus
8 photos, each with 150 sec exposure at ISO 800
Averaged together, then brightness and contrast enhanced.