Astronomy is a natural science that deals with the study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy is one of the oldest sciences. Prehistoric cultures left behind astronomical artifacts such as the Egyptian monuments, Nubian monuments and Stonehenge, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

Leaflet from Royal Greenwich Observatory.

Information about interesting stars and planets in the galaxy, as well as astral bodies outside the Milky Way. Includes photos.

Multi Unit Spectroscopic Explorer. A second generation integral field spectrograph for the VLT. Proposed to European Southern Observatory (ESO) by the Centre de Recherche Astronomique de Lyon (CRAL).

Show universe in terms of distance from Earth center. Includes such things as satellites, planets, stars, nebulae, and galaxies, out to cosmic microwave background radiation from the Big Bang.

All about infrared astronomy from NASA's infrared astronomy center: Discovery of infrared, what is infrared and infrared astronomy, history, the infrared universe, gallery, activities, discoveries, missions and a lot of links to IR astronomy sites.

A web encyclopedia. Over 500 entries, ranging from definitions to full articles.

Provides introductory information about galaxies, the big bang, stars, the solar system, planets, asteroids, comets, astronomical events and astronomy related news.

Offers information on astronomy and space science including news, events, blogs, images, videos and links to other sites. It is written and compiled by experts.

Astronomical internet resources from the National Radio Astronomy Observatory.

Information and articles on astronomy, space and related topics. Also features a friendly forum and a telescope buyer's FAQ page.

Gives overview of the solar system, the Milky Way galaxy, extrasolar planets, cosmology and astrophotography. Includes images, additional resources, and forums.

Resources, searchable forums and searchable lists of organizations providing astronomy services.

Index with graphics and illustrations about stars, the Solar System, cosmology and Galileo.

Fun facts and trivia relating to astronomy, space, science fiction movies. Most trivia items are submitted by users.

General astronomy tutorial, education links, web courses, documents at the UCSD Center for Astrophysics and Space Sciences.

Explores the latest research in astronomy, with overviews of planets and deep-space issues, oberving tips for constellations and what can be seen in the sky tonight.

Introductory article provided by Citizendium, a developing encyclopedia project.

List of links for those, who want to examine theories that are on the fringe of accepted scientific thought that are related connected to astronomy. A few examples are astrology, UFO's, the "Face" on Mars, and ancient astronaut theory.

The use of multiple telescopes to produce high resolution images - commonly used at most modern observatories. A literature review article.

Computes the position, brightness, and other observable characteristics of celestial bodies, as well as the circumstances of astronomical phenomena. Includes information on calendars and related topics.

Contains 3D maps of the universe zooming out from the nearest stars to the scale of the galaxy and out to the surrounding superclusters and finally to the scale of the known universe.

Facts and statistical information about planets, moons, constellations, stars, galaxies, and Messier objects.