C56, (NGC 246) A nice bright Planetary Nebula
An unusually bluish planetary nebula. It is about 10 degrees below the celestial equator, and can best be seen between late summer and early winter. Although a similar nebula, the owl nebula (M97) is much better known, C56, sometimes called the Skull, is actually  bigger and brighter than its cousin. Planetary nebulae are the puffed off material that once made up a star about the size of our sun. During most of the lifetime of such stars, hydrogen is fused into helium. Toward the end, when most of the hydrogen has become helium, the central area where conditions are the most hot and dense, starts fusing the helium into carbon. This is a much more energetic process. The gravity of the star is no longer sufficient to hold this fusion process  and so the overlaying layers get pushed and blown away. The expelled helium overburden, lit up by the remaining white hot core gives the blue color, and the reddish hue is what little hydrogen remained. The central star in this image, with the slightly bluish halo around it, is the remnant white hot carbonaceous core. (called a white dwarf star) Actually, if you look closely, you will notice that the central star is slightly oblong compared to the others nearby. This is because you are seeing two stars, and there is a foreground star, which is a little above and right and otherwise unassociated with C56, which is almost in front of the white dwarf core. Considering the size of the C56 nebula, and its presumed proximity to us, and its relative brightness, there is surprisingly little in the literature about it. It's distance is unlisted and untested, though suspected to be 1500 light years or less. The remnant core is known to be one of the hottest white dwarfs around at over 200,000 deg K (our sun is 5,400 K). and recently some evidence has indicated there is a very close orbiting companion around the core, which therefore must have influenced the creation and character of the surrounding nebula.

10" F6.3 Schmidt Cassegrain telescope. TeleVue coma corrector changing the effective f ratio to 7.5, Hutech P2 light polution filter. Astro Modified Canon T2i camera at Prime focus
8 photos of 600 seconds each at ISO 1600
All 8 photos aligned, then averaged together into one with ImagesPlus, and then brightness, color and contrast enhanced.