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The Nordic Optical Telescope (NOT) telescope in ~ Roque de los Muchachos Observatory in June 2001. The height of the observatory above the Atlantic ocean ensures that it is almost always over the clouds. Image courtesy of Wikipedia.

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What is a Telescope?

A telescope is one instrument the aids in the monitoring of far objects through collecting electromagnetic radiation (such together visible light). The first known helpful telescopes were designed in the Netherlands at the start of the 17th century, making use of glass lenses. They uncovered use in terrestrial applications and astronomy. Within a few decades, the mirroring telescope was invented, which offered mirrors. In the 20th century many brand-new types the telescopes to be invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Words telescope now refers to a wide variety of instruments detecting various regions of the electromagnetic spectrum, and in some situations other types of detectors.

Types of Telescopes I

Refracting Telescope:

A refracting or refractor telescope is a form of optical telescope that offers a lens together its objective to form an picture (also referred to a dioptric telescope). The refracting telescope architecture was originally offered in spy glasses and astronomical telescopes however is likewise used because that long emphasis camera lenses. Although large refracting telescopes were really popular in the second fifty percent of the 19th century, for many research purposes the refracting telescope has actually been superseded by the mirroring telescope.

8-inch (20 cm) refractor at the Observatories in ~ Chabot an are & Science facility in Oakland, California. Credit: Wikipedia

Reflecting Telescope

A mirroring telescope (also referred to as a reflector) is one optical telescope which provides a single or mix of bent mirrors the reflect light and kind an image. The mirroring telescope was developed in the 17th century as an alternative to the refracting telescope which, at the time, was a design that endured from significant chromatic aberration. Although showing telescopes develop other types of optical aberrations, it is a style that permits for very big diameter objectives. Almost every one of the major telescopes used in astronomy research are reflectors. Reflecting telescopes come in many style variations and may employ extra optical aspects to improve photo quality or ar the photo in a mechanically beneficial position. Due to the fact that reflecting telescopes usage mirrors, the design is sometimes referred to as a “catoptric” telescope. Showing telescopes selection is size – from a backyard telescope come the Hubble telescope in planet orbit.

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Meade 114EQ-AR Equatorial Reflector Telescope. Credit: MeadeThe Hubble space Telescope as checked out from the departing room Shuttle Atlantis, flying Servicing Mission 4 (STS-125), the fifth and also latest human being spaceflight to it. Image from NASA.

Types of Telescope II

The name “telescope” consists a wide range of instruments. Most detect electromagnetic radiation, but there are major differences in just how astronomers should go around collecting irradiate (electromagnetic radiation) in different frequency bands. Telescopes might be divide by the wavelength of light they detect:

Optical Telescope:

An optical telescope gathers and also focuses light largely from the visible part of the electromagnetic spectrum (although some job-related in the infrared and also ultraviolet). Optical telescopes increase the noticeable angular dimension of far-off objects as well as their apparent brightness. In order because that the photo to be observed, photographed, studied, and also sent come a computer, telescopes work-related by use one or an ext curved optical elements, commonly made native glass lenses and/or mirrors, to conference light and other electromagnetic radiation to bring that irradiate or radiation to a focal point. Optical telescopes are supplied for astronomy and also in plenty of non-astronomical instruments, including: theodolites (including transits), spotting scopes, monoculars, binoculars, camera lenses, and also spyglasses. There room three main optical types:

1. The refracting telescope which supplies lenses to form an image.2. The showing telescope which provides an setup of mirrors to kind an image.3. The catadioptric telescope which offers mirrors combined with lenses to form an image.

Beyond these an easy optical species there are plenty of sub-types of varying optical architecture classified by the task they carry out such together Astrographs, Comet seekers, Solar telescope, etc.

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Typical optical refractor telescope picture by Jim Mills indigenous Fotolia.com

Radio Telescopes:

Radio telescopes are directional radio antennas offered for radio astronomy. The dishes room sometimes created of a conductive cable mesh who openings are smaller than the wavelength being observed. Multi-element Radio telescopes are created from bag or larger groups of these dishes come synthesize large ‘virtual’ apertures that are similar in dimension to the separation in between the telescopes; this procedure is known as aperture synthesis. Together of 2005, the current record selection size is countless times the width of the Earth—utilizing space-based very Long Baseline Interferometry (VLBI) telescopes such as the Japanese HALCA (Highly progressed Laboratory because that Communications and also Astronomy) VSOP (VLBI room Observatory Program) satellite. Aperture synthetic is now likewise being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and also aperture masking interferometry at single reflecting telescopes. Radio telescopes are additionally used to collect microwave radiation, i beg your pardon is provided to collection radiation when any type of visible light is obstructed or faint, such as from quasars. Some radio telescopes are supplied by program such together SETI and also the Arecibo Observatory to find for extraterrestrial life.

The Arecibo Radio Telescope in Puerto Rico. Image courtesy of SETI.

X-Ray Telescopes:

X-ray telescopes have the right to use X-ray optics, such as a Wolter telescopes composed of ring-shaped ‘glancing’ winter made of hefty metals that space able come reflect the rays just a couple of degrees. The mirrors are usually a section of a rotated parabola and a hyperbola, or ellipse. In 1952, Hans Wolter outlined 3 means a telescope can be developed using only this type of mirror. Examples of one observatory making use of this kind of telescope space the Einstein Observatory, ROSAT, and the Chandra X-Ray Observatory. By 2010, Wolter concentrating X-ray telescopes are possible up to 79 keV.

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Chandra X-Ray Observatory in Space. NASA Image.

Gamma-ray Telescopes:

Gamma-ray telescopes are usually ~ above Earth-orbiting satellites or high-flying balloons due to the fact that the Earth’s atmosphere is opaque to this component of the electromagnetic spectrum. However, high power x-rays and also gamma-rays do not kind an photo in the same way as telescopes at visible wavelengths. An example of this kind of telescope is the Fermi Gamma-ray space Telescope. The detection of really high power gamma rays, with much shorter wavelength and higher frequency than regular gamma rays, requires further specialization. An example of this form of observatory is VERITAS. Really high power gamma-rays room still photons, choose visible light, conversely, cosmic-rays includes particles choose electrons, protons, and also heavier nuclei.A exploration in 2012 may allow focusing gamma-ray telescopes. At photon energizes higher than 700 keV, the table of contents of refraction beginning to rise again.

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Very Energetic Radiation Imaging Gamma beam Telescope range System . Photo courtesy that the Fred Lawrence Whipple Observatory

Using Multiple photos from lot of Telescopes:

Different types of telescope, operating in various wavelength bands, carry out different information around the very same object. With each other they administer a much more comprehensive understanding.

A 6′ broad view the the Crab nebula supernova remnant, viewed at various wavelengths of light by miscellaneous telescopes. Credit: NASA