There are wide range of telescopes. One important classification is the type of radiation the telescope is detecting, and they are Optical telescopes, Radio telescopes, X-ray telescopes, Gamma-ray telescopes, Cosmic-ray telescopes, etc. Most telescopes detect electromagnetic radiation, but there are major differences in how astronomers must go about collecting light (electromagnetic radiation) in different frequency bands. Another classification of telescopes is by location: ground telescope, space telescope, or flying telescope. Telescopes may also be classified as to whether they are operated by professional astronomers or amateur astronomers. A vehicle or permanent campus containing one or more telescopes or other instruments is called an observatory.

Optical Telescopes

An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum (although some work in the infrared and ultraviolet). Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness. In order for the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements. Optical telescopes are usually made from glass—lenses, and/or mirrors to gather light and other electromagnetic radiation to bring that light or radiation to a focal point. Optical telescopes are used for astronomy and in many non-astronomical instruments, including: theodolites (including transits), spotting scopes, monoculars, binoculars, camera lenses, and spyglasses. Different types of optical telescopes are:

  • Visible light telescope
  • Ultraviolet telescope, shorter wavelengths than visible light
  • X-ray telescope, shorter wavelengths than ultraviolet light
  • Infrared telescope, longer wavelengths than visible light
  • Submillimetre telescopes, longer wavelengths than infrared light

Radio Telescopes

Radio telescopes are directional radio antennas used for radio astronomy. The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the wavelength being observed. Multi-element Radio telescopes are constructed from pairs or larger groups of these dishes to synthesize large ‘virtual’ apertures that are similar in size to the separation between the telescopes; this process is known as aperture synthesis.

Special High Energy Particle Telescopes

  • X-Ray Telescopes
  • Gamma-Ray Telescopes
  • Cosmic-Ray Telescopes
  • Neutrino Telescopes
  • Gravitational Wave Telescopes
  • Solar Telescopes