So you want to contribute to the science of astronomy, but you haven't yet gotten around to earning your Ph.D.? No problem. Amateur astronomers have more opportunities than ever to participate in professional research. If you have a computer and an Internet connection, you're there.

Professional astronomers collect a multitude of data each year using some of the world's largest telescopes. The data are typically stored in online databases. Increasingly, many researchers are turning to amateur astronomers to help make sense of this information deluge. Datasets available to interested amateurs are as diverse as the scientists doing the research.

Internet-based astronomy is popular with amateurs for several reasons. First, these celestial sleuths can opt to bring their astronomy skills inside and avoid wind, rain, cold, and light-compromised sky. Unfettered access to researchers' online data is another benefit of using your computer instead of your backyard telescope. And seasoned observers can broaden their knowledge of a particular astronomical subject. Also, there's a sense of belonging that comes from joining forces with others striving for the same goals.

One of the first virtual-astronomy projects to bring amateurs and professionals together is the SETI@home program. Launched in 1999, the Search for Extraterrestrial Intelligence (SETI) program enlists the help of amateur astronomers using their home computers. Participants run a free program that downloads and analyzes radio telescope data. For more information, visit http://setiathome.berkeley.edu.

If you're interested in participating in the search for extrasolar planets, you might try the Systemic project. Astronomers at the University of California, Santa Cruz, have created a simulation that generated a virtual database of 100,000 stars and their planetary systems. The simulation also includes stars' radial-velocity profiles. Users can download a program that allows them to discover and characterize planets within this dataset. Visit their site for more information on Systemic.

William Bianco is an amateur astronomer who embraces internet-based astronomy. To learn about his virtual-astronomy pursuits, read "Amateur astronomers pursue next great discovery."

SETI@home and Systemic are but two of the virtual-astronomy programs available to amateur astronomers. A simple Internet search will turn up many more.