Selected General Astronomy Links
The Sky (Sky Maps and Simulations)
Skymaps.com - Free whole sky charts and objects to view for the month.
WikiSky - The sky in great detail, zoomable, including images from the Sloan Digital Sky Survey.
Solar System Simulator — images, movies, orbits, and more.
Bright Comets Information - Information and charts (updated weekly) about 'bright' comets.
Heaven's Above - Real-time satellite, ISS, and Space Shuttle orbital pass information, maps, and star charts.
Images (and information)
Astronomy Picture of the Day (APOD) - A different astronomy and space science related image is featured each day, along with a brief explanation.
Amateur Astronomy Picture of the Day (AAPOD) - the best Amateur Astronomy images on the internet and a new AAPOD2 award winner daily
Hubble Space Telescope Images - An extensive and searchable catalogue of images collected by the Hubble Space Telescope.
SOHO and Heliospheric Observatory - Official site with mission information on the spaceborn solar observatory. Includes current solar images and data.
Astronomy News
Science at NASA - News and features about NASA research.
Universe Today - Space exploration and astronomy news brought to you from around the Internet, updated daily.
Organizations
The Association of Lunar & Planetary Observers (ALPO) - A medium for advancing and conducting work by both professional and amateur astronomers who share an interest in Solar System observations.
International DarkSky Association - A non-profit member organization that teaches others how to preserve the night sky through factsheets, law references, pictures, and web resources.
Astronomical League - The Astronomical League is composed of over two hundred local amateur astronomical societies from all across the United States. Together they form one of the largest amateur astronomical organizations in the world.
Miscellaneous
Astronomy Glossary - Definitions for some of the most common terms used in astronomy and space exploration.
Eclipse Home Page - This excellent resource contains maps and tables for 7000 years of eclipses and includes information on eclipse photography.
NASA/JPL Calendar - A list of all major space related events provided by the Jet Propulsion Laboratory, USA. Includes launches, conferences, astronomical events, ...
Bad Astronomy - Myths and misconceptions. Includes an introduction, brief biography, and discussion board.
Space Weather - Forecasts of solar flares and geomagnetic storms, plus daily animations of the sun
Astronomy Links - If you don't see what you want on this list of links, it probably doesn't exist. Over 1000 astronomy-related links.
Amateur Telescope Optics - Information about optical aberrations in amateur telescopes. Includes principles of imaging with detailed review of primary aberrations.
Publications
Sky & Telescope Magazine - the Essential Magazine of Astronomy. News, observing tips, how-to advice, and more!
Astronomy Magazine - Source for news in astronomy, reports on astronomical discoveries, and NASA space missions.