Great Image: Cat's Eye

An endless variety of a images populate our night sky, such as the death of a star as shown here in the Cat's Eye Nebula. Just the idea of a halo 5 light years across is amazing, large enough to include both our Sun and Alpha Centauri. By the way, a variation on this image was cited in one of my earlier posts. 

Here is the explanation from NASA's Astronomy Picture of the Day: 

The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its more familiar outlines are seen in the brighter central region of the nebula in this impressive wide-angle view. But the composite image combines many short and long exposures to also reveal an extremely faint outer halo. At an estimated distance of 3,000 light-years, the faint outer halo is over 5 light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. More recently, some planetary nebulae are found to have halos like this one, likely formed of material shrugged off during earlier episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years. Visible on the left, some 50 million light-years beyond the watchful planetary nebula, lies spiral galaxy NGC 6552. 

Image Credit & Copyright: Josh Smith