Array ( [0] => {{short description|Instrument that makes distant objects appear magnified}} [1] => {{Other uses|Telescope (disambiguation)}} [2] => {{pp-move-indef}} [3] => {{Use dmy dates|date=August 2021}} [4] => [[File:100inchHooker.jpg|thumb|The 100-inch (2.54 m) Hooker [[reflecting telescope]] at [[Mount Wilson Observatory]] near Los Angeles, USA, used by [[Edwin Hubble]] to measure galaxy redshifts and discover the general expansion of the universe.]] [5] => [6] => A '''telescope''' is a device used to observe distant objects by their emission, [[Absorption (electromagnetic radiation)|absorption]], or [[Reflection (physics)|reflection]] of [[electromagnetic radiation]].{{cite web|url=https://www.ahdictionary.com/word/search.html?q=TELESCOPE|title= Telescope |website=The American Heritage Dictionary |access-date=12 July 2018|archive-date=11 March 2020|archive-url=https://web.archive.org/web/20200311113032/https://www.ahdictionary.com/word/search.html?q=TELESCOPE|url-status=live}} Originally it was an [[optical instrument]] using [[lens]]es, [[curved mirror]]s, or a combination of both to observe distant objects – an [[optical telescope]]. Nowadays, the word "telescope" is defined as a wide range of instruments capable of detecting different regions of the [[electromagnetic spectrum]], and in some cases other types of detectors. [7] => [8] => The first known practical telescopes were [[refracting telescope]]s with glass [[lens]]es and were invented in the [[Netherlands]] at the beginning of the 17th century. They were used for both terrestrial applications and [[astronomy]]. [9] => [10] => The [[reflecting telescope]], which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. [11] => [12] => In the 20th century, many new types of telescopes were invented, including [[radio telescope]]s in the 1930s and [[infrared telescope]]s in the 1960s. [13] => [14] => == Etymology == [15] => The word '''''telescope''''' was coined in 1611 by the Greek mathematician [[Giovanni Demisiani]] for one of [[Galileo Galilei]]'s instruments presented at a banquet at the [[Accademia dei Lincei]].[[#Reference-Sobel-2000|Sobel (2000, p.43)]], [[#Reference-Drake-1978|Drake (1978, p.196)]]Rosen, Edward, ''The Naming of the Telescope'' (1947) In the ''[[Starry Messenger]]'', Galileo had used the [[Latin]] term {{lang|la|perspicillum}}. The root of the word is from the [[Ancient Greek]] τῆλε, [[romanized]] ''tele'' 'far' and σκοπεῖν, ''skopein'' 'to look or see'; τηλεσκόπος, ''teleskopos'' 'far-seeing'.{{cite book |first=Albert |last=Jack |title=They Laughed at Galileo: How the Great Inventors Proved Their Critics Wrong |date=2015 |publisher=Skyhorse |isbn=978-1629147581}} [16] => [17] => ==History== [18] => {{main|History of the telescope}} [19] => [20] => [[File:Galileu Galilei 1608-2008=400 anos do telescópio - panoramio.jpg|thumb|17th- century telescope]] [21] => The earliest existing record of a telescope was a 1608 patent submitted to the government in the [[Netherlands]] by Middelburg spectacle maker [[Hans Lipperhey]] for a [[refracting telescope]].[http://galileo.rice.edu/sci/instruments/telescope.html galileo.rice.edu ''The Galileo Project > Science > The Telescope'' by Al Van Helden: The Hague discussed the patent applications first of Hans Lipperhey of Middelburg, and then of ] {{Webarchive|url=https://web.archive.org/web/20040623033108/http://galileo.rice.edu/sci/instruments/telescope.html |date=23 June 2004 }}[[Jacob Metius]] of Alkmaar... another citizen of Middelburg, [[Zacharias Janssen]] is sometimes associated with the invention The actual inventor is unknown but word of it spread through Europe. [[Galileo Galilei|Galileo]] heard about it and, in 1609, built his own version, and made his telescopic observations of celestial objects.{{cite web|url=https://www.nasa.gov/audience/forstudents/9-12/features/telescope_feature_912.html|title=NASA – Telescope History|website=www.nasa.gov|access-date=11 July 2017|archive-date=14 February 2021|archive-url=https://web.archive.org/web/20210214151151/https://www.nasa.gov/audience/forstudents/9-12/features/telescope_feature_912.html|url-status=live}}{{cite book|url=https://books.google.com/books?id=Lq1rd1ecFCYC&pg=PA15|title=Profiles in Colonial History|first=Aleck|last=Loker|date=20 November 2017|publisher=Aleck Loker|via=Google Books|isbn=978-1-928874-16-4|access-date=12 December 2015|archive-date=27 May 2016|archive-url=https://web.archive.org/web/20160527140225/https://books.google.com/books?id=Lq1rd1ecFCYC&pg=PA15|url-status=live}} [22] => [23] => The idea that the [[Objective (optics)|objective]], or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope.{{cite book|url=https://books.google.com/books?id=2LZZginzib4C&q=intitle:Stargazer+digges+coins&pg=PA40|title=Stargazer: The Life and Times of the Telescope|first=Fred|last=Watson|date=20 November 2017|publisher=[[Allen & Unwin]]|via=Google Books|isbn=978-1-74176-392-8|access-date=21 November 2020|archive-date=2 March 2021|archive-url=https://web.archive.org/web/20210302184233/https://books.google.com/books?id=2LZZginzib4C&q=intitle:Stargazer+digges+coins&pg=PA40|url-status=live}} The potential advantages of using [[parabolic reflector|parabolic mirrors]]—reduction of [[spherical aberration]] and no [[chromatic aberration]]—led to many proposed designs and several attempts to build [[reflecting telescope]]s.Attempts by [[Niccolò Zucchi]] and [[James Gregory (astronomer and mathematician)|James Gregory]] and theoretical designs by [[Bonaventura Cavalieri]], [[Marin Mersenne]], and Gregory among others In 1668, [[Isaac Newton]] built the first practical reflecting telescope, of a design which now bears his name, the [[Newtonian telescope|Newtonian reflector]].{{cite book |last=Hall |first=A. Rupert |title=Isaac Newton: Adventurer in Thought |publisher=[[Cambridge University Press]] |year=1992 |isbn=9780521566698 |page=67}} [24] => [25] => The invention of the [[achromatic lens]] in 1733 partially corrected color aberrations present in the simple lens{{cite web |url=http://www.britannica.com/biography/Chester-Moor-Hall |title=Chester Moor Hall |website=[[Encyclopædia Britannica]] |accessdate=25 May 2016 |archive-date=17 May 2016 |archive-url=https://web.archive.org/web/20160517172124/http://www.britannica.com/biography/Chester-Moor-Hall |url-status=live }} and enabled the construction of shorter, more functional refracting telescopes.{{Citation needed|date=August 2022}} Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing [[speculum metal]] mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932.{{cite book|url=http://www.cambridge.org/uk/astronomy/features/amateur/files/p28-4.pdf|title= The Cambridge Encyclopedia of Amateur Astronomy |chapter=Chapter Two: Equipment |page=33 |last=Bakich |first=Michael E. |publisher=Cambridge University Press |date= 10 July 2003 |isbn=9780521812986 |archive-url=https://web.archive.org/web/20080910020928/http://www.cambridge.org/uk/astronomy/features/amateur/files/p28-4.pdf |archive-date=2008-09-10}} The maximum physical size limit for refracting telescopes is about {{convert|1|m|in|abbr=off|sp=us}}, dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than {{convert|10|m|ft|abbr=off|sp=us}}, and work is underway on several 30-40m designs.{{cite web |first=Karl |last=Tate |url=https://www.space.com/22505-worlds-largest-telescopes-explained-infographic.html |title=World's Largest Reflecting Telescopes Explained (Infographic) |date=August 30, 2013 |publisher=Space.com |access-date=20 August 2022 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820034258/https://www.space.com/22505-worlds-largest-telescopes-explained-infographic.html |url-status=live }} [26] => [27] => The 20th century also saw the development of telescopes that worked in a wide range of [[Wavelength|wavelengths]] from [[radio telescope|radio]] to [[gamma-ray telescope|gamma-rays]]. The first purpose-built radio telescope went into operation in 1937. Since then, a large variety of complex astronomical instruments have been developed. [28] => [29] => == In space == [30] => {{Main|Space telescope}} [31] => [32] => Since the atmosphere is opaque for most of the electromagnetic spectrum, only a few bands can be observed from the Earth's surface. These bands are visible – near-infrared and a portion of the radio-wave part of the spectrum.{{Cite web |last=Stierwalt |first=Everyday Einstein Sabrina |title=Why Do We Put Telescopes in Space? |url=https://www.scientificamerican.com/article/why-do-we-put-telescopes-in-space/ |access-date=2022-08-20 |website=Scientific American |language=en |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820004401/https://www.scientificamerican.com/article/why-do-we-put-telescopes-in-space/ |url-status=live }} For this reason there are no X-ray or far-infrared ground-based telescopes as these have to be observed from orbit. Even if a wavelength is observable from the ground, it might still be advantageous to place a telescope on a satellite due to issues such as clouds, [[astronomical seeing]] and [[light pollution#Effect on astronomy|light pollution]].{{Cite web |last=Siegel |first=Ethan |title=5 Reasons Why Astronomy Is Better From The Ground Than In Space |url=https://www.forbes.com/sites/startswithabang/2018/03/22/5-reasons-why-astronomy-is-better-from-the-ground-than-in-space/ |access-date=2022-08-20 |website=Forbes |language=en |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820004557/https://www.forbes.com/sites/startswithabang/2018/03/22/5-reasons-why-astronomy-is-better-from-the-ground-than-in-space/ |url-status=live }} [33] => [34] => The disadvantages of launching a space telescope include cost, size, maintainability and upgradability.{{Cite web |last=Siegel |first=Ethan |title=This Is Why We Can't Just Do All Of Our Astronomy From Space |url=https://www.forbes.com/sites/startswithabang/2019/11/27/this-is-why-we-cant-just-do-all-of-our-astronomy-from-space/ |access-date=2022-08-20 |website=Forbes |language=en |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820004551/https://www.forbes.com/sites/startswithabang/2019/11/27/this-is-why-we-cant-just-do-all-of-our-astronomy-from-space/ |url-status=live }} [35] => [36] => Some examples of space telescopes from NASA are the Hubble Space Telescope that detects visible light, ultraviolet, and near-infrared wavelengths, the Spitzer Space Telescope that detects infrared radiation, and the Kepler Space Telescope that discovered thousands of exoplanets.{{cite web |author1=Brennan, Pat |author2=NASA |title=Missons/Discovery |url=https://exoplanets.nasa.gov/discovery/missions/#age-of-discovery-5-000-exoplanets |website=NASA's exoplanet-hunting space telescopes |access-date=17 September 2023 |date=26 July 2022}} The latest telescope that was launched was the James Webb Space Telescope on December 25, 2021, in Kourou, French Guiana. The Webb telescope detects infrared light.{{cite web |author1=Space Telescope Science Institution |author2=NASA |title=Quick Facts |url=https://webbtelescope.org/quick-facts |website=Webb Space Telescope |access-date=17 September 2023 |date=19 July 2023}} [37] => [38] => == By electromagnetic spectrum == [39] => [[File:Crab Nebula in Multiple Wavelengths 2.png|alt=Radio, infrared, visible, ultraviolet, x-ray and gamma ray|thumb|400x400px|Six views of the [[Crab Nebula]] at different wavelengths of light]] [40] => The name "telescope" covers a wide range of instruments. Most detect [[electromagnetic radiation]], but there are major differences in how astronomers must go about collecting light (electromagnetic radiation) in different frequency bands. [41] => [42] => As wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it is possible to make very tiny antenna). The near-infrared can be collected much like visible light; however, in the far-infrared and submillimetre range, telescopes can operate more like a radio telescope. For example, the [[James Clerk Maxwell Telescope]] observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna.{{Cite web|url=http://astro-canada.ca/_en/a2111.html|title=The James-Clerk-Maxwell Observatory|last=ASTROLab du parc national du Mont-Mégantic|date=January 2016|website=Canada under the stars|language=en|access-date=16 April 2017|archive-date=5 February 2011|archive-url=https://web.archive.org/web/20110205193130/http://astro-canada.ca/_en/a2111.html|url-status=live}} On the other hand, the [[Spitzer Space Telescope]], observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the [[Hubble Space Telescope]] with [[Wide Field Camera 3]] can observe in the frequency range from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light).{{Cite web|url=http://www.spacetelescope.org/about/general/instruments/wfc3/|title=Hubble's Instruments: WFC3 – Wide Field Camera 3|website=www.spacetelescope.org|language=en|access-date=16 April 2017|archive-date=12 November 2020|archive-url=https://web.archive.org/web/20201112014826/https://www.spacetelescope.org/about/general/instruments/wfc3/|url-status=live}} [43] => [44] => With photons of the shorter wavelengths, with the higher frequencies, glancing-incident optics, rather than fully reflecting optics are used. Telescopes such as [[TRACE]] and [[Solar and Heliospheric Observatory|SOHO]] use special mirrors to reflect [[extreme ultraviolet]], producing higher resolution and brighter images than are otherwise possible. A larger aperture does not just mean that more light is collected, it also enables a finer angular resolution. [45] => [46] => Telescopes may also be classified by location: ground telescope, [[space telescope]], or [[flying telescope]]. They may also be classified by whether they are operated by [[astronomer|professional astronomers]] or [[amateur astronomer]]s. A vehicle or permanent campus containing one or more telescopes or other instruments is called an [[observatory]]. [47] => [48] => === Radio and submilimeter === [49] => {{main|Radio telescope|Radio astronomy|Submillimetre astronomy}} [50] => [[File:ALMA Greater than the Sum of its Parts (cropped).jpg|alt=see caption|left|thumb|Three radio telescopes belonging to the [[Atacama Large Millimeter Array]]]] [51] => Radio telescopes are [[Directional antenna|directional]] [[radio antennas]] that typically employ a large dish to collect radio waves. The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the [[wavelength]] being observed. [52] => [53] => Unlike an optical telescope, which produces a magnified image of the patch of sky being observed, a traditional radio telescope dish contains a single receiver and records a single time-varying signal characteristic of the observed region; this signal may be sampled at various frequencies. In some newer radio telescope designs, a single dish contains an array of several receivers; this is known as a [[Focal-plane array (radio astronomy)|focal-plane array]]. [54] => [55] => By collecting and correlating signals simultaneously received by several dishes, high-resolution images can be computed. Such multi-dish arrays are known as [[astronomical interferometer]]s and the technique is called [[aperture synthesis]]. The 'virtual' apertures of these arrays are similar in size to the distance between the telescopes. As of 2005, the record array size is many times the diameter of the Earth – using space-based [[very-long-baseline interferometry]] (VLBI) telescopes such as the Japanese [[HALCA]] (Highly Advanced Laboratory for Communications and Astronomy) VSOP (VLBI Space Observatory Program) satellite.{{Cite web |title=Observatories Across the Electromagnetic Spectrum |url=https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum_observatories1.html |access-date=2022-08-20 |website=imagine.gsfc.nasa.gov |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820005838/https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum_observatories1.html |url-status=live }} [56] => [57] => Aperture synthesis is now also being applied to optical telescopes using [[Optical interferometry#Astronomical optical interferometry|optical interferometers]] (arrays of optical telescopes) and [[aperture masking interferometry]] at single reflecting telescopes. [58] => [59] => Radio telescopes are also used to collect [[microwave radiation]], which has the advantage of being able to pass through the atmosphere and interstellar gas and dust clouds. [60] => [61] => Some radio telescopes such as the [[Allen Telescope Array]] are used by programs such as [[Search for Extraterrestrial Intelligence|SETI]]{{Cite journal |last=Dalton |first=Rex |date=2000-08-01 |title=Microsoft moguls back search for ET intelligence |journal=Nature |language=en |volume=406 |issue=6796 |pages=551 |doi=10.1038/35020722 |pmid=10949267 |s2cid=4415108 |issn=1476-4687|doi-access=free }} and the [[Arecibo Observatory]] to search for extraterrestrial life.{{Cite journal |last=Tarter |first=Jill |date=September 2001 |title=The Search for Extraterrestrial Intelligence (SETI) |url=https://www.annualreviews.org/doi/10.1146/annurev.astro.39.1.511 |journal=Annual Review of Astronomy and Astrophysics |language=en |volume=39 |issue=1 |pages=511–548 |doi=10.1146/annurev.astro.39.1.511 |bibcode=2001ARA&A..39..511T |s2cid=261531924 |issn=0066-4146 |access-date=20 August 2022 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820010640/https://www.annualreviews.org/doi/10.1146/annurev.astro.39.1.511 |url-status=dead }}{{Cite web |author1=Nola Taylor Tillman |date=2016-08-02 |title=SETI & the Search for Extraterrestrial Life |url=https://www.space.com/33626-search-for-extraterrestrial-intelligence.html |access-date=2022-08-20 |website=Space.com |language=en |archive-date=17 August 2022 |archive-url=https://web.archive.org/web/20220817113408/https://www.space.com/33626-search-for-extraterrestrial-intelligence.html |url-status=live }} [62] => [63] => === Infrared === [64] => {{main|Infrared telescope|Infrared astronomy}} [65] => [66] => ===Visible light=== [67] => {{main|Optical telescope|Visible-light astronomy}} [68] => [[File:Auxilary VLT telescope.png|alt=Dome-like telescope with extruding mirror mount|thumb|One of four auxiliary telescopes belong to the [[Very Large Telescope]] array]] [69] => An optical telescope gathers and [[Focus (optics)|focuses]] light mainly from the visible part of the electromagnetic spectrum.{{Cite book|url=https://books.google.com/books?id=5wX9aHqfBS0C&pg=PA111|title=The Search for Life Continued: Planets Around Other Stars|last=Jones|first=Barrie W.|date=2 September 2008|publisher=Springer Science & Business Media|isbn=978-0-387-76559-4|language=en|access-date=12 December 2015|archive-date=8 March 2020|archive-url=https://web.archive.org/web/20200308111927/https://books.google.com/books?id=5wX9aHqfBS0C&pg=PA111|url-status=live}} Optical telescopes increase the apparent [[angular size]] of distant objects as well as their apparent [[brightness]]. For the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements, usually made from glass [[lens]]es and/or [[mirror]]s, 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: ''[[theodolite]]s'' (including ''transits''), ''[[spotting scope]]s'', ''[[monocular]]s'', ''[[binoculars]],'' ''[[camera lens]]es'', and ''spyglasses''. There are three main optical types: [70] => *The [[refracting telescope]] which uses lenses to form an image.{{Cite web |author1=Lauren Cox |date=2021-10-26 |title=Who Invented the Telescope? |url=https://www.space.com/21950-who-invented-the-telescope.html |access-date=2022-08-20 |website=Space.com |language=en |archive-date=16 July 2013 |archive-url=https://web.archive.org/web/20130716103207/https://www.space.com/21950-who-invented-the-telescope.html |url-status=live }} [71] => *The [[reflecting telescope]] which uses an arrangement of mirrors to form an image.{{Cite journal |title=1918PA.....26..525R Page 525 |url=https://adsabs.harvard.edu/full/1918PA.....26..525R |access-date=2022-08-20 |journal=Popular Astronomy |bibcode=1918PA.....26..525R |last1=Rupert |first1=Charles G. |year=1918 |volume=26 |page=525 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820090239/https://adsabs.harvard.edu/full/1918PA.....26..525R |url-status=live }} [72] => *The [[Catadioptric#Catadioptric telescopes|catadioptric telescope]] which uses mirrors combined with lenses to form an image. [73] => [74] => A [[Fresnel imager]] is a proposed ultra-lightweight design for a space telescope that uses a [[Fresnel lens]] to focus light.{{Cite web |title=Telescope could focus light without a mirror or lens |url=https://www.newscientist.com/article/dn13820-telescope-could-focus-light-without-a-mirror-or-lens/ |access-date=2022-08-20 |website=New Scientist |language=en-US |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820084508/https://www.newscientist.com/article/dn13820-telescope-could-focus-light-without-a-mirror-or-lens/ |url-status=live }}{{Cite journal |last1=Koechlin |first1=L. |last2=Serre |first2=D. |last3=Duchon |first3=P. |date=2005-11-01 |title=High resolution imaging with Fresnel interferometric arrays: suitability for exoplanet detection |url=https://www.aanda.org/articles/aa/abs/2005/44/aa2880-05/aa2880-05.html |journal=Astronomy & Astrophysics |language=en |volume=443 |issue=2 |pages=709–720 |doi=10.1051/0004-6361:20052880 |arxiv=astro-ph/0510383 |bibcode=2005A&A...443..709K |s2cid=119423063 |issn=0004-6361 |access-date=20 August 2022 |archive-date=3 December 2021 |archive-url=https://web.archive.org/web/20211203102019/https://www.aanda.org/articles/aa/abs/2005/44/aa2880-05/aa2880-05.html |url-status=live }} [75] => [76] => Beyond these basic optical types there are many sub-types of varying optical design classified by the task they perform such as [[astrograph]]s,{{Cite web |title=Celestron Rowe-Ackermann Schmidt Astrograph – Astronomy Now |url=https://astronomynow.com/2016/06/01/celestron-rowe-ackermann-schmidt-astrograph/ |access-date=2022-08-20 |language=en-US |archive-date=1 October 2022 |archive-url=https://web.archive.org/web/20221001151936/https://astronomynow.com/2016/06/01/celestron-rowe-ackermann-schmidt-astrograph/ |url-status=live }} [[comet seeker]]s{{Cite web |title=Telescope (Comet Seeker) |url=https://www.si.edu/object/nmah_1183753 |access-date=2022-08-20 |website=Smithsonian Institution |language=en |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820084507/https://www.si.edu/object/nmah_1183753 |url-status=live }} and [[solar telescope]]s.{{Cite journal |last=Stenflo |first=J. O. |date=2001-01-01 |title=Limitations and Opportunities for the Diagnostics of Solar and Stellar Magnetic Fields |journal=Magnetic Fields Across the Hertzsprung-Russell Diagram |url=https://ui.adsabs.harvard.edu/abs/2001ASPC..248..639S |volume=248 |pages=639 |bibcode=2001ASPC..248..639S |access-date=20 August 2022 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820084507/https://ui.adsabs.harvard.edu/abs/2001ASPC..248..639S |url-status=live }} [77] => [78] => === Ultraviolet === [79] => {{Main|2 = Ultraviolet astronomy}} [80] => Most ultraviolet light is absorbed by the Earth's atmosphere, so observations at these wavelengths must be performed from the upper atmosphere or from space.{{Cite book |last=Allen |first=C. W. |url=https://www.worldcat.org/oclc/40473741 |title=Allen's astrophysical quantities |date=2000 |publisher=AIP Press |others=Arthur N. Cox |isbn=0-387-98746-0 |edition=4th |location=New York |oclc=40473741}}{{Cite journal |last1=Ortiz |first1=Roberto |last2=Guerrero |first2=Martín A. |date=2016-06-28 |title=Ultraviolet emission from main-sequence companions of AGB stars |journal=Monthly Notices of the Royal Astronomical Society |volume=461 |issue=3 |pages=3036–3046 |doi=10.1093/mnras/stw1547 |issn=0035-8711|doi-access=free |arxiv=1606.09086 }} [81] => [82] => === X-ray === [83] => {{main|X-ray telescope|X-ray astronomy}} [84] => [[File:ASTRO-H soft X-ray mirror.jpg|alt=see caption|left|thumb|[[Hitomi (satellite)|''Hitomi'' telescope]]'s X-ray focusing mirror, consisting of over two hundred [[Concentric objects|concentric]] aluminium shells]] [85] => [[X-ray]]s are much harder to collect and focus than electromagnetic radiation of longer wavelengths. X-ray telescopes can use [[X-ray optics]], such as [[Wolter telescope]]s composed of ring-shaped 'glancing' mirrors made of [[heavy metals]] that are able to reflect the rays just a few [[degree (angle)|degrees]]. The mirrors are usually a section of a rotated [[parabola]] and a [[hyperbola]], or [[ellipse]]. In 1952, [[Hans Wolter]] outlined 3 ways a telescope could be built using only this kind of mirror.{{Citation |title=Glancing Incidence Mirror Systems as Imaging Optics for X-rays |author=Wolter, H. |journal=Annalen der Physik |volume=10 |issue=1 |pages=94–114 |date=1952 |postscript=. |doi=10.1002/andp.19524450108|bibcode = 1952AnP...445...94W }}{{Citation |title=Verallgemeinerte Schwarzschildsche Spiegelsysteme streifender Reflexion als Optiken für Röntgenstrahlen |author=Wolter, H. |journal=Annalen der Physik |volume=10 |pages=286–295 |date=1952 |postscript=. |doi=10.1002/andp.19524450410 |issue=4–5|bibcode = 1952AnP...445..286W }} Examples of space observatories using this type of telescope are the [[Einstein Observatory]],{{Cite journal |last1=Giacconi |first1=R. |last2=Branduardi |first2=G. |last3=Briel |first3=U. |last4=Epstein |first4=A. |last5=Fabricant |first5=D. |last6=Feigelson |first6=E. |last7=Forman |first7=W. |last8=Gorenstein |first8=P. |last9=Grindlay |first9=J. |last10=Gursky |first10=H. |last11=Harnden |first11=F. R. |last12=Henry |first12=J. P. |last13=Jones |first13=C. |last14=Kellogg |first14=E. |last15=Koch |first15=D. |date=June 1979 |title=The Einstein /HEAO 2/ X-ray Observatory |journal=The Astrophysical Journal |language=en |volume=230 |pages=540 |doi=10.1086/157110 |bibcode=1979ApJ...230..540G |s2cid=120943949 |issn=0004-637X |doi-access=free }} [[ROSAT]],{{Cite web |title=DLR - About the ROSAT mission |url=https://www.dlr.de/content/en/articles/missions-projects/past-missions/rosat/rosat-mission.html |access-date=2022-08-20 |website=DLRARTICLE DLR Portal |language=en |archive-date=16 August 2022 |archive-url=https://web.archive.org/web/20220816133434/https://www.dlr.de/content/en/articles/missions-projects/past-missions/rosat/rosat-mission.html |url-status=live }} and the [[Chandra X-ray Observatory]].{{Cite journal |last=Schwartz |first=Daniel A. |date=2004-08-01 |title=The development and scientific impact of the chandra x-ray observatory |url=https://www.worldscientific.com/doi/abs/10.1142/S0218271804005377 |journal=International Journal of Modern Physics D |volume=13 |issue=7 |pages=1239–1247 |doi=10.1142/S0218271804005377 |arxiv=astro-ph/0402275 |bibcode=2004IJMPD..13.1239S |s2cid=858689 |issn=0218-2718 |access-date=20 August 2022 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820013024/https://www.worldscientific.com/doi/abs/10.1142/S0218271804005377 |url-status=live }}{{Cite journal |last=Madejski |first=Greg |year=2006 |title=Recent and Future Observations in the X‐ray and Gamma‐ray Bands: Chandra, Suzaku, GLAST, and NuSTAR |url=https://aip.scitation.org/doi/abs/10.1063/1.2141828 |journal=AIP Conference Proceedings |volume=801 |issue=1 |pages=21–30 |doi=10.1063/1.2141828 |arxiv=astro-ph/0512012 |bibcode=2005AIPC..801...21M |s2cid=14601312 |issn=0094-243X |access-date=20 August 2022 |archive-date=28 April 2022 |archive-url=https://web.archive.org/web/20220428135227/https://aip.scitation.org/doi/abs/10.1063/1.2141828 |url-status=live }} In 2012 the [[NuSTAR]] X-ray Telescope was launched which uses [[Wolter telescope]] design optics at the end of a long [[Deployable structure|deployable]] mast to enable photon energies of 79 keV.{{cite web|url=http://www.nustar.caltech.edu/about-nustar/instrumentation/optics|title=NuStar: Instrumentation: Optics|url-status=dead|archive-url=https://web.archive.org/web/20101101113623/http://www.nustar.caltech.edu/about-nustar/instrumentation/optics|archive-date=1 November 2010}}{{Cite journal |last1=Hailey |first1=Charles J. |last2=An |first2=HongJun |last3=Blaedel |first3=Kenneth L. |last4=Brejnholt |first4=Nicolai F. |last5=Christensen |first5=Finn E. |last6=Craig |first6=William W. |last7=Decker |first7=Todd A. |last8=Doll |first8=Melanie |last9=Gum |first9=Jeff |last10=Koglin |first10=Jason E. |last11=Jensen |first11=Carsten P. |last12=Hale |first12=Layton |last13=Mori |first13=Kaya |last14=Pivovaroff |first14=Michael J. |last15=Sharpe |first15=Marton |editor-first1=Monique |editor-first2=Stephen S |editor-first3=Tadayuki |editor-last1=Arnaud |editor-last2=Murray |editor-last3=Takahashi |date=2010-07-29 |title=The Nuclear Spectroscopic Telescope Array (NuSTAR): optics overview and current status |url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/7732/77320T/The-Nuclear-Spectroscopic-Telescope-Array-NuSTAR--optics-overview-and/10.1117/12.857654.full |journal=Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray |publisher=SPIE |volume=7732 |pages=197–209 |doi=10.1117/12.857654|bibcode=2010SPIE.7732E..0TH |s2cid=121831705 }} [86] => [87] => === Gamma ray === [88] => {{main|2 = Gamma-ray astronomy}} [89] => [[File:Compton Gamma Ray Observatory grappeled by Atlantis (S37-99-056).jpg|thumb|The [[Compton Gamma Ray Observatory]] released into orbit by the Space Shuttle in 1991]] [90] => Higher energy X-ray and gamma ray telescopes refrain from focusing completely and use [[coded aperture]] masks: the patterns of the shadow the mask creates can be reconstructed to form an image. [91] => [92] => X-ray and Gamma-ray telescopes are usually installed on high-flying balloons{{Cite journal |last1=Braga |first1=João |last2=D’Amico |first2=Flavio |last3=Avila |first3=Manuel A. C. |last4=Penacchioni |first4=Ana V. |last5=Sacahui |first5=J. Rodrigo |last6=Santiago |first6=Valdivino A. de |last7=Mattiello-Francisco |first7=Fátima |last8=Strauss |first8=Cesar |last9=Fialho |first9=Márcio A. A. |date=2015-08-01 |title=The protoMIRAX hard X-ray imaging balloon experiment |url=https://www.aanda.org/articles/aa/abs/2015/08/aa26343-15/aa26343-15.html |journal=Astronomy & Astrophysics |language=en |volume=580 |pages=A108 |doi=10.1051/0004-6361/201526343 |arxiv=1505.06631 |bibcode=2015A&A...580A.108B |s2cid=119222297 |issn=0004-6361 |access-date=20 August 2022 |archive-date=29 January 2022 |archive-url=https://web.archive.org/web/20220129081951/https://www.aanda.org/articles/aa/abs/2015/08/aa26343-15/aa26343-15.html |url-status=live }}{{Cite web |author1=Brett Tingley |date=2022-07-13 |title=Balloon-borne telescope lifts off to study black holes and neutron stars |url=https://www.space.com/balloon-telescope-xl-calibur-x-rays-black-holes |access-date=2022-08-20 |website=Space.com |language=en |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820025636/https://www.space.com/balloon-telescope-xl-calibur-x-rays-black-holes |url-status=live }} or Earth-orbiting [[satellite]]s since the [[Earth's atmosphere]] is opaque to this part of the electromagnetic spectrum. An example of this type of telescope is the [[Fermi Gamma-ray Space Telescope]] which was launched in June 2008.{{Cite journal |last1=Atwood |first1=W. B. |last2=Abdo |first2=A. A. |last3=Ackermann |first3=M. |last4=Althouse |first4=W. |last5=Anderson |first5=B. |last6=Axelsson |first6=M. |last7=Baldini |first7=L. |last8=Ballet |first8=J. |last9=Band |first9=D. L. |last10=Barbiellini |first10=G. |last11=Bartelt |first11=J. |last12=Bastieri |first12=D. |last13=Baughman |first13=B. M. |last14=Bechtol |first14=K. |last15=Bédérède |first15=D. |title=The Large Area Telescope on Thefermi Gamma-Ray Space Telescopemission |date=2009-06-01 |url=https://iopscience.iop.org/article/10.1088/0004-637X/697/2/1071 |journal=The Astrophysical Journal |volume=697 |issue=2 |pages=1071–1102 |doi=10.1088/0004-637X/697/2/1071 |arxiv=0902.1089 |bibcode=2009ApJ...697.1071A |s2cid=26361978 |issn=0004-637X |access-date=20 August 2022 |archive-date=20 August 2022 |archive-url=https://web.archive.org/web/20220820014256/https://iopscience.iop.org/article/10.1088/0004-637X/697/2/1071 |url-status=live }}{{Cite journal |last1=Ackermann |first1=M. |last2=Ajello |first2=M. |last3=Baldini |first3=L. |last4=Ballet |first4=J. |last5=Barbiellini |first5=G. |last6=Bastieri |first6=D. |last7=Bellazzini |first7=R. |last8=Bissaldi |first8=E. |last9=Bloom |first9=E. D. |last10=Bonino |first10=R. |last11=Bottacini |first11=E. |last12=Brandt |first12=T. J. |last13=Bregeon |first13=J. |last14=Bruel |first14=P. |last15=Buehler |first15=R. |date=2017-07-13 |title=Search for Extended Sources in the Galactic Plane Using Six Years of''Fermi''-Large Area Telescope Pass 8 Data above 10 GeV |journal=The Astrophysical Journal |language=en |volume=843 |issue=2 |pages=139 |doi=10.3847/1538-4357/aa775a |arxiv=1702.00476 |bibcode=2017ApJ...843..139A |s2cid=119187437 |issn=1538-4357 |doi-access=free }} [93] => [94] => The detection of very high energy gamma rays, with shorter wavelength and higher frequency than regular gamma rays, requires further specialization. Such detections can be made either with the [[IACT|Imaging Atmospheric Cherenkov Telescopes]] (IACTs) or with Water Cherenkov Detectors (WCDs). Examples of IACTs are [[High Energy Stereoscopic System|H.E.S.S.]]{{Cite journal |last=Aharonian |first=F. |last2=Akhperjanian |first2=A. G. |last3=Bazer-Bachi |first3=A. R. |last4=Beilicke |first4=M. |last5=Benbow |first5=W. |last6=Berge |first6=D. |last7=Bernlöhr |first7=K. |last8=Boisson |first8=C. |last9=Bolz |first9=O. |last10=Borrel |first10=V. |last11=Braun |first11=I. |last12=Breitling |first12=F. |last13=Brown |first13=A. M. |last14=Bühler |first14=R. |last15=Büsching |first15=I. |date=2006-10-01 |title=Observations of the Crab nebula with HESS |url=https://www.aanda.org/articles/aa/abs/2006/39/aa5351-06/aa5351-06.html |journal=Astronomy & Astrophysics |language=en |volume=457 |issue=3 |pages=899–915 |doi=10.1051/0004-6361:20065351 |issn=0004-6361|arxiv=astro-ph/0607333 }} and [[VERITAS]]{{Cite journal |last1=Krennrich |first1=F. |last2=Bond |first2=I. H. |last3=Boyle |first3=P. J. |last4=Bradbury |first4=S. M. |last5=Buckley |first5=J. H. |last6=Carter-Lewis |first6=D. |last7=Celik |first7=O. |last8=Cui |first8=W. |last9=Daniel |first9=M. |last10=D'Vali |first10=M. |last11=de la Calle Perez |first11=I. |last12=Duke |first12=C. |last13=Falcone |first13=A. |last14=Fegan |first14=D. J. |last15=Fegan |first15=S. J. |date=2004-04-01 |title=VERITAS: the Very Energetic Radiation Imaging Telescope Array System |url=https://www.sciencedirect.com/science/article/pii/S1387647303003610 |journal=New Astronomy Reviews |series=2nd VERITAS Symposium on the Astrophysics of Extragalactic Sources |language=en |volume=48 |issue=5 |pages=345–349 |doi=10.1016/j.newar.2003.12.050 |bibcode=2004NewAR..48..345K |hdl=10379/9414 |issn=1387-6473|hdl-access=free }}{{Cite journal |last1=Weekes |first1=T. C. |last2=Cawley |first2=M. F. |last3=Fegan |first3=D. J. |last4=Gibbs |first4=K. G. |last5=Hillas |first5=A. M. |last6=Kowk |first6=P. W. |last7=Lamb |first7=R. C. |last8=Lewis |first8=D. A. |last9=Macomb |first9=D. |last10=Porter |first10=N. A. |last11=Reynolds |first11=P. T. |last12=Vacanti |first12=G. |date=1989-07-01 |title=Observation of TeV Gamma Rays from the Crab Nebula Using the Atmospheric Cerenkov Imaging Technique |url=https://ui.adsabs.harvard.edu/abs/1989ApJ...342..379W |journal=The Astrophysical Journal |volume=342 |pages=379 |doi=10.1086/167599 |bibcode=1989ApJ...342..379W |s2cid=119424766 |issn=0004-637X |access-date=20 August 2022 |archive-date=11 April 2023 |archive-url=https://web.archive.org/web/20230411132918/https://ui.adsabs.harvard.edu/abs/1989ApJ...342..379W |url-status=live }} with the next-generation gamma-ray telescope- [[Cherenkov Telescope Array|CTA]], currently under construction. [[High Altitude Water Cherenkov Experiment|HAWC]] and [[Large High Altitude Air Shower Observatory|LHAASO]] are examples of gamma-ray detectors based on the Water Cherenkov Detectors. [95] => [96] => A discovery in 2012 may allow focusing gamma-ray telescopes. At photon energies greater than 700 keV, the index of refraction starts to increase again.{{cite web|url=http://physicsworld.com/cws/article/news/2012/may/09/silicon-prism-bends-gamma-rays|title=Silicon 'prism' bends gamma rays – Physics World|date=9 May 2012|access-date=15 May 2012|archive-date=12 May 2013|archive-url=https://web.archive.org/web/20130512101728/http://physicsworld.com/cws/article/news/2012/may/09/silicon-prism-bends-gamma-rays|url-status=live}} [97] => [98] => ==Lists of telescopes== [99] => {{colbegin|colwidth=20em}} [100] => *[[List of optical telescopes]] [101] => *[[List of largest optical reflecting telescopes]] [102] => *[[List of largest optical refracting telescopes]] [103] => *[[List of largest optical telescopes historically]] [104] => *[[List of radio telescopes]] [105] => *[[List of solar telescopes]] [106] => *[[List of space observatories]] [107] => *[[List of telescope parts and construction]] [108] => *[[List of telescope types]] [109] => {{colend}} [110] => [111] => ==See also== [112] => {{colbegin|colwidth=20em}} [113] => * [[Air mass (astronomy)|Airmass]] [114] => * [[Amateur telescope making]] [115] => * [[Angular resolution]] [116] => * [[ASCOM (standard)|ASCOM]] open standards for computer control of telescopes [117] => * [[Bahtinov mask]] [118] => * [[Binoculars]] [119] => * [[Bioptics (device)|Bioptic telescope]] [120] => * [[Carey mask]] [121] => * [[Dew shield]] [122] => * [[Dynameter]] [123] => * [[f-number]] [124] => * [[First light (astronomy)|First light]] [125] => * [[Hartmann mask]] [126] => * [[Keyhole problem]] [127] => * [[Microscope]] [128] => * [[List of planetariums|Planetariums]] [129] => * [[Remote Telescope Markup Language]] [130] => * [[Robotic telescope]] [131] => * [[Timeline of telescope technology]] [132] => * [[Timeline of telescopes, observatories, and observing technology]] [133] => {{colend}} [134] => [135] => ==References== [136] => {{reflist}} [137] => [138] => ==Further reading== [139] => *{{Citation [140] => |last=Elliott [141] => |first=Robert S. [142] => |date=1966 [143] => |title=Electromagnetics [144] => |publisher=[[McGraw-Hill]] [145] => }} [146] => * {{Cite book |last=King |first=Henry C. |url=https://www.worldcat.org/oclc/6025190 |title=The history of the telescope |date=1979 |publisher=Dover Publications |others=H. Spencer Jones |isbn=0-486-23893-8 |location=New York |oclc=6025190}} [147] => * {{Cite book |last=Pasachoff |first=Jay M. |author-link=Jay Pasachoff |url=https://www.worldcat.org/oclc/7734917 |title=Contemporary astronomy |date=1981 |publisher=Saunders College Pub |isbn=0-03-057861-2 |edition=2nd |location=Philadelphia |oclc=7734917}} [148] => *{{Citation [149] => |last1=Rashed [150] => |first1=Roshdi [151] => |last2=Morelon [152] => |first2=Régis [153] => |date=1996 [154] => |title=Encyclopedia of the History of Arabic Science [155] => |volume=1 & 3 [156] => |publisher=[[Routledge]] [157] => |isbn=978-0-415-12410-2 [158] => |title-link=Encyclopedia of the History of Arabic Science [159] => }} [160] => *{{cite book|last=Sabra|first=A.I. |author2=Hogendijk, J.P. |date=2003|title=The Enterprise of Science in Islam: New Perspectives|publisher=[[MIT Press]]|pages=85–118|isbn=978-0-262-19482-2}} [161] => *{{Citation [162] => |doi=10.1068/p3210 [163] => |last1=Wade [164] => |first1=Nicholas J. [165] => |last2=Finger [166] => |first2=Stanley [167] => |date=2001 [168] => |title=The eye as an optical instrument: from camera obscura to Helmholtz's perspective [169] => |journal=Perception [170] => |volume=30 [171] => |issue=10 [172] => |pages=1157–1177 [173] => |pmid=11721819 [174] => |s2cid=8185797 [175] => }} [176] => * {{Cite book |last=Watson |first=Fred |url=https://www.worldcat.org/oclc/173996168 |title=Stargazer : the life and times of the telescope |date=2007 |publisher=Allen & Unwin |isbn=978-1-74176-392-8 |location=Crows Nest, NSW |oclc=173996168}} [177] => [178] => ==External links== [179] => {{wikiquote}} [180] => {{Commons|Telescope}} [181] => *[http://telescopes.stardate.org/ ''Galileo to Gamma Cephei – The History of the Telescope''] {{Webarchive|url=https://web.archive.org/web/20130508014125/http://telescopes.stardate.org/ |date=8 May 2013 }} [182] => *[http://galileo.rice.edu/sci/instruments/telescope.html ''The Galileo Project – The Telescope'' by Al Van Helden] [183] => *[http://www.aip.org/history/cosmology/tools/tools-first-telescopes.htm "The First Telescopes". Part of an exhibit from Cosmic Journey: A History of Scientific Cosmology] {{Webarchive|url=https://web.archive.org/web/20080409125917/http://www.aip.org/history/cosmology/tools/tools-first-telescopes.htm |date=9 April 2008 }} by the American Institute of Physics [184] => *{{cite EB1911 |wstitle=Telescope |volume=26 |pages=557–573 |first1=Harold Dennis |last1=Taylor |first2=David |last2=Gill |short=1}} [185] => *[http://spiff.rit.edu/classes/phys230/lectures/nonoptical/nonoptical.html Outside the Optical: Other Kinds of Telescopes] [186] => *{{cite web|last=Gray|first=Meghan|title=Telescope Diameter|url=http://www.sixtysymbols.com/videos/telescope.htm|work=Sixty Symbols|publisher=[[Brady Haran]] for the [[University of Nottingham]]|author2=Merrifield, Michael |date=2009}} [187] => [188] => {{Astronomy navbox}} [189] => {{Portal bar|Astronomy|Outer space|Solar System|Stars}} [190] => {{Authority control}} [191] => [192] => [[Category:Telescopes| ]] [193] => [[Category:Astronomical imaging]] [194] => [[Category:Astronomical instruments]] [195] => [[Category:Dutch inventions]] [] => )
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Telescope

A telescope is an optical instrument designed to magnify and focus light for observation of distant objects. It gathers and amplifies electromagnetic radiation such as visible light, infrared radiation, or radio waves.

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It gathers and amplifies electromagnetic radiation such as visible light, infrared radiation, or radio waves. Telescopes have been used for centuries to explore the vastness of the universe, allowing astronomers and scientists to study celestial objects and phenomena. They have played a crucial role in advancing our knowledge of astronomy, from discovering planets and stars to understanding the fundamental properties of the universe. Telescopes come in various types, including refracting telescopes, reflecting telescopes, and radio telescopes, each with its own strengths and limitations. Over the years, telescopes have evolved immensely in terms of technology and functionality, with advancements like space-based telescopes and adaptive optics. Through continuous innovation, telescopes continue to revolutionize our understanding of the cosmos and contribute to numerous scientific discoveries.

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