Telescope

A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light). The first known practical Terran telescopes were invented in the Netherlands at the beginning of the 17th century CE, using glass lenses. They found use in terrestrial applications and astronomy.

Within a few decades, the reflecting telescope was invented, which used mirrors. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. The word telescope now refers to a wide range of instruments detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors.

The word "telescope" (from the Greek tele, "far" and skopein, "to look or see"; teleskopos "far-seeing") was coined in 1611 CE by the Greek mathematician Giovanni Demisiani.

Today's Telescopes are classified by the wavelengths of light they detect:


 * Cosmic Ray telescopes, using shorter wavelengths than Gamma rays


 * Gamma Ray telescopes, using shorter wavelengths that X-Ray


 * X-ray telescopes, using shorter wavelengths than ultraviolet light


 * Ultraviolet telescopes, using shorter wavelengths than visible light


 * Optical telescopes, using visible light


 * Infrared telescopes, using longer wavelengths than visible light

Telescopes may also be classified by location: ground,  space or atmospheric flight. They may also be classified by whether they are operated by professional or amateur astronomers. A vehicle or permanent location containing one or more telescopes or other instruments is called an observatory.
 * Submillimeter telescopes, using longer wavelengths than infrared light