It looks like a soap bubble, but it's about five light-years across and floating in deep space.

Three amateur astronomers in California found the beautiful planetary nebula a year ago, and they have now been officially recognized as its discoverers.

Officially named PN G75.5+1.7, the "soap bubble nebula" is the remnant of a dying star that shed its outer shell about 22,000 years ago. It lies about 4,000 light-years away in the constellation Cygnus.

Chemical engineer Dave Jurasevich was the first to see it on July 6, 2008, at the Mount Wilson Observatory near Pasadena, Calif.

Nearly two weeks later, on July 17, 2008, medical professionals Keith Quattrocchi and Mel Helm, both of the Fresno area, independently spotted it from their Sierra Remote Observatories high in the California mountain range.

The discoveries were reported to the International Astronomical Union, which has now credited all three men.

As Jurasevich notes on his Web site, increasingly powerful telescopes now make it possible for amateur astronomers to make significant contributions to science.

"Compared to the level of relatively simple instrumentation available to amateur astronomers just a few decades ago," he writes, "the powerful and technically advanced equipment of today can and does yield meaningful results."

• Click here for an explanation of the nebula from the National Optical Astronomy Observatory.

• Click here for Dave Jurasevich's Web page on the discovery.

• Click here for Keith Quattrocchi and Mel Helm's page on it.