Telescope

The word telescope now refers to all instruments that collect electromagnetic waves and bundle in order to observe distant objects and processes better. It was used until well into the 20th century, synonymous with the telescope. The term is formed from the ancient Greek τῆλε ( Tele) " far" and σκοπεῖν ( skopein ) "observe", " spy ". He was indeed engraved only in modern times, yet already knew the Ancient Greek word τηλεσκόπος ( teleskópos ) " well- looking ".

The first telescope is considered the Galilean telescope, also called 'Dutch telescope ". It was invented by Dutch spectacle maker Hans Lippershey 1608 and further developed in the aftermath of Galileo Galilei.

After Pierre Borel, however, Zacharias Janssen and his father should have only then made ​​the true inventor of the telescope to be (1610 ) and Hans Lippershey a telescope after he had knowledge of Janssens received invention.

For the term " telescope"

The term " telescope" goes beyond the optical astronomy (visible light, ultraviolet and infrared) addition to the range of X-ray or radio emission. It is sometimes further generalized to the detector array, allowing a reconstruction of the direction of incidence of the detected radiation. One example is the term " neutrino telescope " is at times used in the literature. Furthermore, the term is also used for optical assemblies that are constructed as an optical telescope, but also are not used for monitoring objects. A telescope, for example, the beam expander (enlarge the beam diameter ) of lasers are used to transmit the beam across longer distances or to reduce its intensity.

Telescope types

Depending on the frequency spectrum or range of wavelengths of electromagnetic radiation are distinguished:

  • Gamma telescopes
  • X-ray telescopes
  • Optical telescopes ( telescopes and reflecting telescopes )
  • Infrared telescopes
  • Radio telescopes.

Apart from the space telescopes, they are dependent on the wavelength of the Astronomical window in which the radiation from the Earth's atmosphere is not or only slightly absorbed. A possible high altitude, climatic dry location is advantageous.

In order to set up telescopes on an astronomical object, they are usually mounted on a mount. Exceptions are fixed large telescopes such as the Arecibo Observatory or space telescopes that are positioned differently.

There is a rich telescope accessories (see below), ranging from filtering through to a wide variety of eyepieces. Ultra-modern hexapod telescope can be aligned with the aid of linear actuators technical freely in all three spatial directions.

Special types

  • Tower Telescope
  • Giant telescope
  • Schiefspiegler
  • Telescopes for airborne astronomy

Major telescopes

Telescopes for visible light (optical telescopes )

The currently largest optical telescopes with primary mirror diameters greater than 8 m are:

  • The two Keck telescopes of the Mauna Kea Observatory
  • The four telescopes of the Very Large Telescope ( VLT) in the Atacama desert in Chile
  • The Gemini telescopes in Hawaii and Chile
  • The Subaru telescope in Hawaii
  • The Hobby - Eberly Telescope in Texas
  • The Southern African Large Telescope ( SALT) in South Africa
  • The Gran Telescopio Canarias in La Palma
  • The Large Binocular Telescope ( LBT ) in Arizona.

Larger telescopes like the European Extremely Large Telescope, or the Giant Magellan Telescope are being planned.

Historically important was among others the Hale telescope on Mount Palomar in California

Other telescopes are listed in the categories Optical Telescope and ground -bound observatory as well as in the list of largest optical telescopes.

Radio telescopes

  • RATAN 600
  • Arecibo Observatory
  • Very Large Array
  • Atacama Large Millimeter Array

Space telescopes

  • Hubble Space Telescope
  • Spitzer telescope

Use of the primary image

Visual observations with smaller telescopes by means of an eyepiece, which is mounted behind the focus, performed. Commercially available small picture or medium format cameras or electronic sensors can be attached here. For large telescopes are located at this point, various accessories such as spectrographs, photometers and cameras.

Large telescopes use the focus of the primary mirror ( the primary focus) for direct observations. Instead of that, in some telescopes there a primary focus cabin, which replaces the secondary mirror. Prior to the introduction of electronic detectors remained there during the entire observation program on an astronomer, today only the instrument is mounted there and controlled from the control room. Other large telescopes conduct the primary image of the main optics of a Coude optical path or optical fibers in its own evaluation space. This allows the use of large analyzers, the weight would otherwise complicate the construction of the mobile assembly of the main optics.

Telescope Accessories

  • Eyepiece
  • Barlow lens
  • Herschel wedge
  • Sun filter
  • Color filter
  • Aperture (optics)
  • CCD camera
  • Mount
  • Finderscope
  • Polarscope
  • Focuser
Las Campanas Observatory Newtonian telescope Space observatory Atmospheric window Hexapod-Telescope W. M. Keck Observatory Mauna Kea Observatories Gemini Observatory Hobby–Eberly Telescope First light (astronomy) Amateur Telescope Making
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