Scientists need help sorting through an unusual digital photo album: pictures of about 1 million galaxies.

They are asking volunteers on the Internet to help classify the galaxies as either elliptical or spiral and note, where possible, in which direction they rotate. It would be the largest galactic census ever compiled, something scientists say would provide new insight into the structure of the universe.

Astronomers say computer programs have been unable to reliably classify the star systems. Without volunteers, researchers would need years to wade through the photographs. With 10,000 to 20,000 people working to classify the galaxies, the process could take as little as a month.

The Web site is www.galaxyzoo.org.