In an article published in the August 2012 issue of The Astronomical Journal, researchers led by Joel Kastner and Rodolfo Montez Jr used Chandra to observe 21 planetary nebulae, all of which lie within about 5,000 light years of Earth.
The four nebulae featured below (the Cat's Eye nebula [NGC 6543], NGC 6826, NGC 7662 and NGC 7009) were among the most stunning to be observed in the course of the survey. These composite images combine X-ray emissions collected by Chandra (colored in purple) with optical emissions gathered by Hubble Space Telescope (colored in red, green and blue).
Click on any image to view in hi-resolution. All images Images via NASA/CXC/RIT/J.Kastner et al. (X-ray); NASA/STScI (optical):
Read more over at NASA.