Astronomy is a branch of science that studies celestial objects and phenomena, including planets, stars, comets, asteroids, galaxies, cosmic radiation, and others. It enables human beings to develop an understanding of the outer space as well as the formation and evolution of the universe. This form of science has been practiced since the ancient times, but it did not become one of the major sciences until the invention of the telescope. Today, professional astronomy is divided into two different branches, namely, theoretical and observational astronomy.

General Astronomy

• What is Astronomy?: An overview of the science of astronomy.
• Astronomy Basics: General information about astronomy.
• Amazing Space: Lots of interesting astronomy facts and images.
• Introduction to Astronomy: A web page that is dedicated to promoting understanding of basic astronomy.
• Astronomy Images: A website with galleries of astronomy pictures.
• Astronomy Resources: Resource page with list of astronomy-related websites.

History

• History of Astronomy: Find out how astronomy evolved from the ancient times to the present.
• Astronomy Timeline: A timeline that provides an account on the development of astronomy over the years.
• Ancient Astronomy: Articles that offer an insight into the practice of astronomy during the ancient times.
• Modern Astronomy History: An overview of the history of modern astronomy.
• Famous Astronomers: List of some of the most important astronomers in history.

Scientific Revolution

• The Scientific Revolution: An article that relates the scientific revolution that resulted from discoveries made by astronomers.
• Galileo and the Scientific Revolution: Discussion on how Galileo contributed to the scientific revolution.
• Astronomy Historical Background: Web page that discusses the development of important concepts of astronomy in history.
• Astronomy and Scientific Revolution: Links to websites that offer detailed information on astronomy and the scientific revolution.

Observational Astronomy

• Stargazing Basics: Learn the basics of stargazing from this magazine.
• Observational Astronomy Methods: Descriptions of methods that are used to observe objects and phenomena in the outer space.
• Observational Astronomy Links: A resource page that links to a wide variety of information about observational astronomy.

Radio Astronomy

• What is Radio Astronomy?: Web page that provides a comprehensive explanation of the basics of radio astronomy.
• Radio Astronomy Basics: A NASA web page that contains information about radio astronomy.
• National Radio Astronomy Observatory: A National Science Foundation facility that conducts research on the invisible universe.
• Radio Astronomy Links: Links to radio astronomy-related websites.

Infrared Astronomy

• Introduction to Infrared Astronomy: Article that explains the science of infrared astronomy.
• Understanding Infrared Astronomy: Find out how infrared astronomy works.
• All about Infrared Astronomy: Learn all the basics of infrared astronomy from this web page.

Optical Astronomy

• National Optical Astronomy Observatory: Official website of the National Optical Astronomy Observatory.
• Optical Astronomy Sites: A list of websites that offer information on optical astronomy.

Ultraviolet Astronomy

• What is Ultraviolet Astronomy?: Definition of ultraviolet astronomy.
• Extreme Ultraviolet Explorer: Web page dedicated to NASA’s Extreme Ultraviolet Explorer.
• Future of Ultraviolet Astronomy: Discover the possibilities of ultraviolet astronomy in the future.

X-Ray Astronomy

• What is X-Ray Astronomy?: A comprehensive introduction to x-ray astronomy.
• X-Ray Astronomy Field Guide: Collection of articles that reveal interesting facts about x-ray astronomy.
• Application of X-Ray Astronomy: The importance of x-ray technology in the study of the outer space.

Gamma-Ray Astronomy

• Gamma-Ray Astronomy: Basic information on gamma-ray astronomy.
• Gamma-Ray Astronomy History: A brief historical account of the science of gamma-ray astronomy.
• High Energy Gamma-Ray Astronomy: An article that explores the occurrences of high energy gamma-rays in outer space.

Astrometry and Celestial Mechanics

• Astrometry Overview: Article that provides a clear explanation of astrometry.
• Celestial Mechanics: Extensive information about celestial mechanics.
• Astrometry Links: A selection of astrometry-related websites.

Theoretical Astronomy

• Guide to Theoretical Astronomy: Recommended resources for those who wish to learn theoretical astronomy.

Subfields of Astronomy

• Types of Astronomy: Descriptions of the different types of astronomy.