Like the real universe, the universe of astronomical information available on the World Wide Web is expanding rapidly. No single list of astronomy- and space-related websites can be 100 percent complete. The following list, compiled and updated regularly by the editors of Sky & Telescope, is geared toward amateur astronomers and space buffs. But it also includes links to other lists of useful resources. Many museums, planetariums, observatories, and astronomy clubs have Web pages too. You'll find them in our Clubs & Organizations directory.

If you'd like to recommend an addition to our list, or if you discover a problem with any current entry, please let us know by sending e-mail to skylinks@SkyandTelescope.com.

• Indexes of Astronomical Websites
• Professional Research
• Amateur Research
• Annual Amateur Events
• Equipment & Telescope Making
• Observing & More!
• Astronomy Education
• Images & Animations
• Astronomy Blogs & Podcasts
• Online Star Charts
• Online Data & Catalogs
• Online Astronomy Newsletters & Web Portals
• Magazines & Journals