Telescope

A telescope is an optical instrument that makes distant objects appear magnified by using an arrangement of lenses or curved mirrors and lenses, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation.

History

The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. They were used for both terrestrial applications and astronomy.

Types of Telescopes

There are three main types of optical telescope:

• Refractors (Dioptrics) which use lenses
• Reflectors (Catoptrics) which use mirrors
• Combined lens-mirror systems (Catadioptrics) such as the Schmidt-Cassegrain and the Maksutov telescope which use both mirrors and lenses.

Function

The telescope's function is to gather light and bring that light to a point where it can be magnified and examined.

See also

• List of telescope types
• History of the telescope
• Astronomical observatory
• Radio telescope
• Space telescope

External links

• Telescope.com
• Sky & Telescope

• 
  100-inch Hooker Telescope
• 
  Galileo's Telescope
• 
  Inside the Ursa Observatory
• 
  Crab Nebula in Multiple Wavelengths
• 
  ALMA Array
• 
  Auxiliary VLT Telescope
• 
  ASTRO-H Soft X-ray Mirror
• 
  Compton Gamma Ray Observatory