It's a trick of the eye, but what a beautiful trick!
The visual effect starts with a sunlike star in the constellation Hydra, about 1,500 light-years from Earth. When that star was nearing the end of its life, it blew away its outer layers of gas to form a blue bubble in space — a planetary nebula known as Abell 33, or PN A66 33. The star fizzled out to become an unremarkable white dwarf near the center of the bubble.
But from Earth's point of view, a brighter star named HD 83535 is shining in the foreground, seemingly just at the edge of the bubble. Together, Abell 33 and HD 83535 create a sparkling diamond ring in space, as seen by the European Southern Observatory's Very Large Telescope in Chile. For more about the image and the telescope, check out the ESO's image advisory.