There are only a few nights that I can image one of the most spectacular nebulae in the sky. I refer to NGC 7293, also known as the Helix Nebula. It has also been referred to as the “eye of God.” Why it has been so difficult to image is because my observatory is situated near trees on the horizon, and unless it is trackable above the trees, I cannot get any image at all.
The Helix has the largest apparent diameter of any planetary nebula. It lies in the constellation Aquarius, which lies low in the southern sky. Looking like a giant circle, the nebula surrounds a dying star that has blown off its outer layers, once its central supply of nuclear fuel was nearly exhausted. The remnant central star is a dense “white dwarf” that can no longer support nuclear reactions. At a distance of 450 light years, it is the closest planetary nebula to earth.
As our sun advances to late middle age, it will expand to a red giant, engulfing the inner planets, including earth. Then, the outer gases will disperse as in the case of the Helix, leaving our sun a white dwarf. The final stage will result in a “black hole” as it dies. Such a fate awaits the star at the center of the Helix.
Below is my image of the Helix with 2 X 2 binning, 35 images stacked, each one minute in length. Be sure to click on it for a larger view.