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Revision 1220480 of "Radiation telescopes" on enwikiversity[[Image:Brorfelde Schmidt Telescope.jpg|thumb|right|200px|The Schmidt Telescope at the former Brorfelde Observatory is now used by amateur astronomers. Credit: [[commons:User:Moeng|Mogens Engelund]].]]
{{complete}}
A '''radiation telescope''' is an instrument designed to collect and focus radiation so as to make distant sources appear nearer.
{{experimental}}
{{primary}}
{{secondary}}
{{tertiary}}
{{research}}
{{article}}
{{lecture}}
{{astronomy}}
{{Materials science}}
{{technology}}
=Notation=
'''Notation''': let the symbol '''Def.''' indicate that a definition is following.
'''Notation''': let the symbols between [ and ] be replacement for that portion of a quoted text.
'''Notation''': let the symbol '''...''' indicate unneeded portion of a quoted text.
Sometimes these are combined as '''[...]''' to indicate that text has been replaced by '''...'''.
=Universals=
To help with definitions, their meanings and intents, there is the learning resource [[theory of definition]].
=Proof of concept=
'''Def.''' "[a] short and/or incomplete [[wikt:realization|realization]] of a certain [[wikt:method|method]] or idea to demonstrate its feasibility"<ref name=ProofofConceptWikt>{{ cite web
|title=proof of concept, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 10,
|year=2012
|url=http://en.wiktionary.org/wiki/proof_of_concept
|accessdate=2013-01-13 }}</ref> is called a '''proof of concept'''.
'''Def.''' evidence that demonstrates that a concept is possible is called '''proof of concept'''.
The proof-of-concept structure consists of
# background,
# procedures,
# findings, and
# interpretation.<ref name=Lehrman>{{ cite journal
|author=Ginger Lehrman and Ian B Hogue, Sarah Palmer, Cheryl Jennings, Celsa A Spina, Ann Wiegand, Alan L Landay, Robert W Coombs, Douglas D Richman, John W Mellors, John M Coffin, Ronald J Bosch, David M Margolis
|title=Depletion of latent HIV-1 infection in vivo: a proof-of-concept study
|journal=Lancet
|month=August 13,
|year=2005
|volume=366
|issue=9485
|pages=549-55
|url=http://www.sciencedirect.com/science/article/pii/S0140673605670985
|arxiv=
|bibcode=
|doi=10.1016/S0140-6736(05)67098-5
|pmid=
|pdf=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1894952/
|accessdate=2012-05-09 }}</ref>
Proof of concept consists of a prototype instrument or device that makes a distant source appear nearer.
=Proof of technology=
"[T]he objective of a proof of technology is to determine the solution to some technical problem, such as how two systems might be integrated or that a certain throughput can be achieved with a given configuration."<ref name=ProofofConceptWikt/>
'''Def.''' "[a]n original object or form which is a basis for other objects, forms, or for its models and generalizations"<ref name=PrototypeWikt>{{ cite web
|title=prototype, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 8,
|year=2013
|url=https://en.wiktionary.org/wiki/prototype
|accessdate=2014-01-03 }}</ref> is called a '''prototype'''.
'''Def.''' "[a]n early sample or model built to test a concept or process"<ref name=PrototypeWikt/> is called a '''prototype'''.
'''Def.''' "[a]n instance of a [[wikt:category|category]] or a [[wikt:concept|concept]] that combines its most representative attributes"<ref name=PrototypeWikt/> is called a '''prototype'''.
'''Def.''' "[t]o test something using the conditions that it was designed to operate under, especially out in the real world instead of in a laboratory or workshop"<ref name=FieldTestWikt>{{ cite web
|title=field-test, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 5,
|year=2012
|url=https://en.wiktionary.org/wiki/field-test
|accessdate=2014-01-03 }}</ref> is called "field-test", or a '''field test'''.
A "proof-of-technology prototype ... typically implements one critical scenario to exercise or stress the highest-priority requirements."<ref name=Liu>{{ cite journal
|author=A. Liu; I. Gorton
|title=Accelerating COTS middleware acquisition: the i-Mate process
|journal=Software, IEEE
|month=March/April
|year=2003
|volume=20
|issue=2
|pages=72-9
|url=http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1184171
|arxiv=
|bibcode=
|doi=10.1109/MS.2003.1184171
|pmid=
|pdf=http://cin.ufpe.br/~redis/intranet/bibliography/middleware/liu-cots03.pdf
|accessdate=2012-02-15 }}</ref>
"[A] proof-of-technology test demonstrates the system can be used"<ref name=Wessel>{{ cite journal
|author=Rhea Wessel
|title=Cargo-Tracking System Combines RFID, Sensors, GSM and Satellite
|journal=RFID Journal
|month=January 25,
|year=2008
|volume=
|issue=
|pages=1-2
|url=http://www.rfidjournal.com/article/pdf/3870/1/1/rfidjournal-article3870.PDF
|arxiv=
|bibcode=
|doi=
|pmid=
|pdf=
|accessdate=2012-02-15 }}</ref>.
"The strongest proof of technology performance is based on consistency among multiple lines of evidence, all pointing to similar levels of risk reduction."<ref name=Rao>{{ cite book
|author=P. Suresh, C. Rao, M.D. Annable and J.W. Jawitz
|title=''In Situ'' Flushing for Enhanced NAPL Site Remediation:
Metrics for Performance Assessment, In: ''Abiotic ''In Situ'' Technologies for Groundwater Remediation Conference''
|publisher=U.S. Environmental Protection Agency
|location=Cincinnati, Ohio
|month=August
|year=2000
|editor=E. Timothy Oppelt
|pages=105
|url=
|arxiv=
|bibcode=
|doi=
|pmid=
|pdf=http://www.afcee.af.mil/shared/media/document/AFD-071003-081.pdf#page=108
|accessdate=2012-02-15 }}</ref>
=Control group=
The findings demonstrate a statistically systematic change from the status quo or the [[control group]].
A control group for a radiation telescope would contain
# an aperture, or an entry avenue into the instrument,
# collimators, or lenses, to concentrate radiation,
# moderators, to systematically reduce the incoming radiation so as to allow determination of incoming direction,
# detectors, or sensors, to convert the incoming radiation into electrical impulses,
# amplifiers, or processors, and
# supports, to provide orientation and stability of all components.
=Astronomy=
[[Image:Mauna Kea observatory.jpg|thumb|left|200px|Sunset over four telescopes of the [[w:Mauna Kea Observatories|Mauna Kea Observatories]] is pictured, from left to right: the [[w:Subaru Telescope|Subaru Telescope]], the twin [[w:W. M. Keck Observatory|Keck I and II telescope]]s, and the [[w:NASA Infrared Telescope Facility|NASA Infrared Telescope Facility]]. Credit: [http://flickr.com/photos/35188692@N00 Alan L].]]
[[Astronomy]] may be accomplished by observation using personal senses, or augmented with the use of instruments. The telescope itself can be moved on or by vehicles along the ground, on water, in the air, or above the Earth's atmosphere, and throughout the nearby [[interplanetary medium]].
Observational astronomy benefits from electronics, mechanisms, tools, and machinery.
"With its high altitude, dry environment, and stable airflow, Mauna Kea's summit is one of the best sites in the world for astronomical observation [at left], and one of the most controversial. Since the creation of an access road in 1964, thirteen telescopes funded by eleven countries have been constructed at the summit. The [[w:Mauna Kea Observatories|Mauna Kea Observatories]] are used for scientific research across the [[w:electromagnetic spectrum|electromagnetic spectrum]] from [[Visual astronomy|visible]] light to radio, and comprise one of the world's largest facilities of their type. Their construction on a "sacred landscape",<ref name="uh-2009">{{ cite web
|title=Mauna Kea Comprehensive Management Plan: UH Management Areas
|url=http://hawaii.gov/dlnr/occl/mauna-kea-management-plan/comprehensive-management-plan
|format=PDF
|last=Institute for Astronomy – University of Hawaii
|publisher=Hawai`i State Department of Land and Natural Resources
|accessdate=August 19, 2010
|date=January 2009 }}</ref> replete with endangered species and ongoing cultural practices, continues to be a topic of debate and protest. Studies are underway to determine their effect on the summit ecology, particularly on the rare [[w:Wēkiu bug|Wēkiu bug]]. It was designated a [[w:National Natural Landmark|National Natural Landmark]] in 1972.<ref name=nnl>{{ cite web
|title=National Natural Landmark
|url=http://www.nature.nps.gov/nnl/site.cfm?Site=MAKE-HI
|publisher=National Park Service
|accessdate=12 December 2012 }}</ref><ref name=MaunaKea>{{ cite web
|title=Mauna Kea, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 4,
|year=2013
|url=http://en.wikipedia.org/wiki/Mauna_Kea
|accessdate=2013-02-05 }}</ref>
"There are nine telescopes working in the visible and infrared spectrum, three in the submillimeter spectrum, and one in the radio spectrum, with mirrors or dishes ranging from {{convert|0.9|m|ft|1|abbr=on}} to {{convert|25|m|ft|0|abbr=on}}.<ref name="telescope-table">{{ cite web
|title=Mauna Kea Telescopes
|url=http://www.ifa.hawaii.edu/mko/telescope_table.shtml
|publisher=Institute for Astronomy – University of Hawaii
|accessdate=August 29, 2010 }}</ref>"<ref name=MaunaKea/>
{{clear}}
=Radiation=
“In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space.”<ref name=Radiation>{{ cite web
|title=Radiation, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 31,
|year=2012
|url=http://en.wikipedia.org/wiki/Radiation
|accessdate=2012-06-02 }}</ref>
'''Def.''' an action or process of throwing or sending out a traveling ray in a line, beam, or stream of small cross section is called '''radiation'''.
'''Def.''' “[t]he shooting forth of anything from a point or surface, like the diverging rays of light; as, the radiation of heat”<ref name=Radiation>{{ cite web
|title=radiation, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 24,
|year=2012
|url=http://en.wiktionary.org/wiki/radiation
|accessdate=2012-07-07 }}</ref> is called '''radiation'''.
Radiation that a particular telescope or a telescope array observes consists of fast moving entities from which information is gathered using spectroscopy, spatial distributions, or temporal distributions. A galaxy cluster that is moving is radiation and an astronomical object to be observed. Entities moving faster than the galaxy such as protons or photons are observables.
=Astrodesy=
On [[Earth]], telescopes are positioned using [[geodesy]], such fields as surveying, structural geology of the underlying ground, and architecture. The availability of manpower is usually missing for extraterrestrial observatories on the [[Moon]], [[Mars]], or [[Venus]]. On the [[International Space Station]], manpower is often available for instrument control and use.
=Telescopes=
[[Image:MENISCAS 180.jpg|thumb|right|200px|This is an optical telescope that may be used for optical and visual astronomy. Credit: .]]
'''Def.''' “[a]ny instrument used in astronomy for observing distant objects”<ref name=TelescopeWikt>{{ cite web
|title=telescope, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 7,
|year=2013
|url=https://en.wiktionary.org/wiki/telescope
|accessdate=2014-01-03 }}</ref> is called a '''telescope'''.
'''Def.''' any "instrument used in [[astronomy]] for observing distant objects (such as a radio telescope)"<ref name=TelescopeWikt/> is called a '''telescope''', or an '''astronomical telescope'''.
{{clear}}
=Aerial telescopes=
[[Image:Aerialtelescope.jpg|thumb|right|200px|An engraving of Huygens 210-foot aerial telescope showing the eyepiece and objective mounts and connecting string. Credit: .]]
“An '''aerial telescope''' is a type of very-long-focal-length [[w:refracting telescope|refracting telescope]] built in the second half of the 17th century that did not use a tube.<ref name=Rice>{{ cite web
|title=The Telescope
|url=http://galileo.rice.edu/sci/instruments/telescope.html
|publisher=The Galileo Project
|accessdate=5 March 2012 }}</ref> Instead, the [[w:Objective (optics)|objective]] was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held the [[w:eyepiece|eyepiece]], which was connected to the objective by a string or connecting rod. By holding the string tight and maneuvering the eyepiece, the observer could aim the telescope at objects in the sky.”<ref name=AerialTelescope>{{ cite web
|title=Aerial telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 16,
|year=2012
|url=http://en.wikipedia.org/wiki/Aerial_telescope
|accessdate=2012-10-08 }}</ref>
“After about 1675, therefore, astronomers did away with the telescope tube. The objective was mounted on a building or pole by means of a ball-joint and aimed by means of a string...”<ref name=Rice/>
{{clear}}
=Early telescopes=
[[Image:Nimrud lens British Museum.jpg|thumb|right|250px|This image is a photo of the [[w:Nimrud lens|Nimrud lens]] in the [[w:British museum|British museum]]. Credit: [[commons:User:Geni|Geni]].]]
"There are indeed ancient tablets that mention astronomers' lenses supported by a golden tube to enlarge the pupil, and in Nineveh a rock crystal [[w:Nimrud lens|lens]] was found (Pettinato 1998). Maybe one day a new archaeological excavation will find a Babylonian telescope for the first time."<ref name=Magli>{{ cite book
|author=Giulio Magli
|title=When the method is lacking, In: ''Mysteries and Discoveries of Archaeoastronomy from Giza to Easter Island''
|publisher=Copernicus Books
|location=Rome, Italy
|month=
|year=2009
|editor=
|pages=97-116
|url=
|bibcode=
|doi=10.1007/978-0-387-76566-2_5
|pmid=
|isbn=978-0-387-76564-8
|pdf=http://www.springerlink.com/content/w2q6g0q252221k0u/fulltext.pdf
|accessdate=2011-10-15 }}</ref>
{{clear}}
=Optics=
"'''Optics''' involves the behavior and properties of [[w:light|light]], including its interactions with [[w:matter|matter]] and the construction of [[w:optical instruments|instruments]] that use or [[w:Photodetector|detect]] it.<ref name=McGrawHill>{{ cite book
|title=McGraw-Hill Encyclopedia of Science and Technology
|edition=5th
|publisher=McGraw-Hill
|year=1993 }}</ref> Optics usually describes the behavior of [[w:visible light|visible]], [[w:ultraviolet|ultraviolet]], and [[w:infrared|infrared]] light. Because light is an [[w:electromagnetic wave|electromagnetic wave]], other forms of [[w:electromagnetic radiation|electromagnetic radiation]] such as [[w:X-ray|X-ray]]s, [[w:microwave|microwave]]s, and [[w:radio wave|radio wave]]s exhibit similar properties.<ref name=McGrawHill />"<ref name=Optics>{{ cite web
|title=Optics, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 1,
|year=2012
|url=http://en.wikipedia.org/wiki/Optics
|accessdate=2012-07-07 }}</ref>
=Colors=
"[B]roadband optical photometry of Centaurs and Kuiper Belt objects from the Keck 10 m, the University of Hawaii 2.2 m, and the Cerro Tololo InterAmerican (CTIO) 1.5 m telescopes [shows] a wide dispersion in the optical colors of the objects, indicating nonuniform surface properties. The color dispersion [may] be understood in the context of the expected steady reddening due to bombardment by the ubiquitous flux of cosmic rays."<ref name=Luu>{{ cite journal
|author=Jane Luu and David Jewitt
|title=Color Diversity among the Centaurs and Kuiper Belt Objects
|journal=The Astronomical Journal
|month=November
|year=1996
|volume=112
|issue=5
|pages=2310-8
|url=http://adsabs.harvard.edu/full/1996AJ....112.2310L
|arxiv=
|bibcode=1996AJ....112.2310L
|doi=
|pmid=
|accessdate=2013-11-05 }}</ref>
=Minerals=
[[Image:Transparency.jpg|thumb|right|200px|This shows a colorless and very clean quartz that is transparent. Credit: [[commons:User:Zimbres|Zimbres]].]]
"'''Quartz''' is the second-most-abundant [[w:mineral|mineral]] in the [[Earth]]'s [[w:continental crust|continental crust]], after [[w:feldspar|feldspar]]. ... Pure quartz, traditionally called ''rock crystal'' (sometimes called ''clear quartz''), is colorless and [[w:transparent materials|transparent]] or [[w:translucent|translucent]]."<ref name=Quartz>{{ cite web
|title=Quartz, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 29,
|year=2012
|url=http://en.wikipedia.org/wiki/Quartz
|accessdate=2012-09-03 }}</ref>
"Bombardment by protostellar cosmic rays may make the rock precursors of [Calcium-aluminum-rich inclusions] CAIs and chondrules radioactive, producing radionuclides found in meteorites that are difficult to obtain with other mechanisms."<ref name=Lee>{{ cite journal
|author=Typhoon Lee, Frank H. Shu and Hsien Shang, Alfred E. Glassgold and K. E. Rehm
|title=Protostellar cosmic rays and extinct radioactivities in meteorites
|journal=The Astrophysical Journal
|month=October 20,
|year=1998
|volume=506
|issue=2
|pages=898-912
|url=http://iopscience.iop.org/0004-637X/506/2/898
|arxiv=
|bibcode=
|doi=10.1086/306284
|pmid=
|accessdate=2013-11-04 }}</ref>
"[[w:Ice core|Ice core]]s contain thin nitrate-rich layers that can be analyzed to reconstruct a history of past events before reliable observations; [this includes] data from Greenland ice cores<ref name=McCracken>{{ cite web
|url=http://www.stuartclark.com/files/thomas-qa.pdf
|title=How do you determine the effects of a solar flare that took place 150 years ago?
|publisher=Stuart Clarks Universe
|accessdate=May 23, 2012 }}</ref> and others. These show evidence that events of [the magnitude of the [[w:Solar storm of 1859|solar storm of 1859]]—as measured by high-energy proton radiation, not geomagnetic effect—occur approximately once per 500 years, with events at least one-fifth as large occurring several times per century.<ref name=McCracken01>{{ cite journal
|author=Kenneth G. McCracken, G. A. M. Dreschhoff, E. J. Zeller, D. F. Smart, M. A. Shea
|title=Solar cosmic ray events for the period 1561–1994 1. Identification in polar ice, 1561–1950
|journal=Journal of Geophysical Research
|volume=106
|issue=A10
|pages=21,585–21,598
|year=2001
|doi=10.1029/2000JA000237
|url=http://www.agu.org/pubs/crossref/2001/2000JA000237.shtml
|accessdate=February 16, 2011
|bibcode=2001JGR...10621585M }}</ref> Less severe storms have occurred in 1921 and 1960, when widespread radio disruption was reported."<ref name=SolarStormof1859>{{ cite web
|title=Solar storm of 1859, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=September 1,
|year=2012
|url=http://en.wikipedia.org/wiki/Solar_storm_of_1859
|accessdate=2012-09-01 }}</ref>
"Ordinary glass is partially [[w:transparency and translucency|transparent]] to UVA but is [[w:opacity (optics)|opaque]] to shorter wavelengths, whereas [[w:fused quartz|silica or quartz glass]], depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.<ref name=sodaline>{{ cite web
| title = Soda Lime Glass Transmission Curve
| url = http://www.sinclairmfg.com/datasheets/optical3.html }}</ref><ref name=katalog>{{ cite web
| title = B270-Superwite Glass Transmission Curve
| url = http://www.pgo-online.com/intl/katalog/curves/B270_kurve.html }}</ref><ref name=floatglass>{{ cite web
| title = Selected Float Glass Transmission Curve
| url = http://www.pgo-online.com/intl/katalog/curves/whitefl_kurve.html }}</ref>"<ref name=Ultraviolet>{{ cite web
|title=Ultraviolet, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 26,
|year=2012
|url=http://en.wikipedia.org/wiki/Ultraviolet
|accessdate=2012-06-26 }}</ref>
{{clear}}
=Theoretical radiation astronomy telescopy=
'''Def.''' "[t]he manufacture and use of telescopes"<ref name=TelescopyWikt>{{ cite web
|title=telescopy, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 1,
|year=2013
|url=http://en.wiktionary.org/wiki/telescopy
|accessdate=2013-07-21 }}</ref> is called '''telescopy'''.
'''Def.''' "[t]he manufacture and use of radio telescopes"<ref name=RadiotelescopyWikt>{{ cite journal
|title=radiotelescopy
|journal=Wiktionary
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 2,
|year=2013
|url=http://en.wiktionary.org/wiki/radiotelescopy
|pdf=
|accessdate=2013-07-21 }}</ref> is called '''radiotelescopy'''.
=Entities=
=Sources=
[[Image:Horizontal cyclotron with glowing beam.jpg|thumb|center|300px|This image shows a beam of accelerated ions (perhaps protons or deuterons) escaping the accelerator and ionizing the surrounding air causing a blue glow. Credit: Lawrence Berkely National Laboratory.]]
[[Image:Synchrotron light.jpeg|thumb|right|200px|The image shows the blue glow given off by the synchrotron beam from the National Synchrotron Light Source. Credit: NSLS, Brookhaven National Laboratory.]]
The image above shows a blue glow in the surrounding air from emitted cyclotron particulate radiation.
At right is an image that shows the blue glow resulting from a beam of relativistic electrons as they slow down. This deceleration produces synchrotron light out of the beam line of the National Synchrotron Light Source.
{{clear}}
=Objects=
=Strong forces=
=Electromagnetics=
=Weak forces=
=Continua=
=Emissions=
=Absorptions=
=Bands=
[[Image:Rosetta.jpg|thumb|right|200px|This is a 3D model of the Rosetta Spacecraft. The individual scientific payloads are highlighted in different colours. Credit: [[w:User:IanShazell|IanShazell]].]]
For elongated dust particles in cometary comas an investigation is performed at 535.0 nm (green) and 627.4 nm (red) peak transmission wavelengths of the [[w:Rosetta (spacecraft)|Rosetta spacecraft]]'s OSIRIS Wide Angle Camera broadband green and red filters, respectively.<ref name=Bertini>{{ cite journal
|author=I. Bertini, N. Thomas, and C. Barbieri
|title=Modeling of the light scattering properties of cometary dust using fractal aggregates
|journal=Astronomy & Astrophysics
|month=January
|year=2007
|volume=461
|issue=1
|pages=351-64
|url=http://www.aanda.org/articles/aa/full/2007/01/aa5461-06/aa5461-06.html
|arxiv=
|bibcode=2007A&A...461..351B
|doi=10.1051/0004-6361:20065461
|pmid=
|pdf=http://www.aanda.org/articles/aa/pdf/2007/01/aa5461-06.pdf
|accessdate=2011-12-08 }}</ref>
{{clear}}
=Backgrounds=
[[Image:Red-blue-noise.gif|frame|The frame demonstrates an example of visual snow-like noise. Credit: .]]
"In astronomical [[w:Charge-coupled device|CCD]] technology, '''background''' is usually referred to the overall optical "noise" of the system, that is, the incoming light on the CCD sensor in absence of light sources. This background can originate from electronic noise in the CCD, from not-well-masked lights nearby the telescope, and so on. An exposure on an empty patch of the sky is also called a background, and is the sum of the system background level plus the sky's one."<ref name=BackgroundAstronomy/>
"A '''background frame''' is often the first exposure in an astronomical observation with a CCD: the frame will then be subtracted from the actual observation result, leaving in theory only the incoming light from the astronomical object being observed."<ref name=BackgroundAstronomy>{{ cite web
|title=Background (astronomy), In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 7,
|year=2010
|url=http://en.wikipedia.org/wiki/Background_(astronomy)
|accessdate=2013-05-03 }}</ref>
{{clear}}
=Meteor telescopes=
[[Image:250mm Rain Gauge.jpg|thumb|upright|left|125 px|The image shows a standard rain gauge. Credit: .]]
Meteor telescopes per se are often other types of telescopes, such as optical telescopes, that happen or are slewed to observe meteors.
At left is a collection device for rain on [[Earth]] as part of [[meteorology]].
There are favorable locations on Earth, Moon and Mars where [[meteorites]] are discovered. These meteorite, or micrometeorite, locations include Antarctica and the equatorial deserts.
{{clear}}
=Cosmic-ray telescopes=
[[Image:HEAO-3.gif|thumb|right|200px|This is an image of HEAO 3. Credit: .]]
[[Image:Pioneer 10-11 - P52a - fx.jpg|thumb|left|150px|The charged particle instrument (CPI) is used to detect cosmic rays in the solar system. Credit: NASA.]]
[[Image:Pioneer 10-11 - P52b - fx.jpg|thumb|left|150px|The cosmic-ray telescope collects data on the composition of the cosmic ray particles and their energy ranges. Credit: NASA.]]
"The [HEAO 3, at right, French-Danish] C-2 experiment measured the relative composition of the isotopes of the primary cosmic rays between beryllium and iron (Z from 4 to 26) and the elemental abundances up to tin (Z=50). Cerenkov counters and [[w:hodoscope|hodoscope]]s, together with the Earth's magnetic field, formed a spectrometer. They determined charge and mass of cosmic rays to a precision of 10% for the most abundant elements over the momentum range from 2 to 25 GeV/c (c=speed of light)."<ref name=HighEnergyAstronomyObservatory3>{{ cite web
|title=High Energy Astronomy Observatory 3, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 4,
|year=2012
|url=http://en.wikipedia.org/wiki/High_Energy_Astronomy_Observatory_3
|accessdate=2012-12-05 }}</ref>
"Recent measurements using the Goddard-University of New Hampshire cosmic-ray telescope [at left] on the ''Pioneer 10'' spacecraft have revealed an anomalous spectrum of nitrogen and oxygen nuclei relative to other nuclei such as He and C, in the energy range 3-30 MeV per nucleon."<ref name=McDonald>{{ cite journal
|author=F. B. McDonald, B. J. Teegarden, and J. H. Trainor and W. R. Webber
|title=The anomalous abundance of cosmic-ray nitrogen and oxygen nuclei at low energies
|journal=The Astrophysical Journal
|month=February 1.
|year=1974
|volume=187
|issue=02
|pages=L105-8
|url=http://adsabs.harvard.edu/full/1974ApJ...187L.105M
|arxiv=
|bibcode=1974ApJ...187L.105M
|doi=10.1086/181407
|pmid=
|pdf=
|accessdate=2012-12-05 }}</ref>
{{clear}}
=Neutron telescopes=
[[Image:Comptel.gif|thumb|left|200px|The Imaging Compton Telescope (COMPTEL) utilizes the Compton Effect and two layers of gamma-ray detectors. Credit: NASA.]]
"In addition to observing gamma rays from a solar flare, [ the Imaging Compton Telescope] COMPTEL is also capable of detecting solar neutrons. Neutron interactions within the instrument occur when an incident solar neutron elastically scatters off a hydrogen nucleus in the liquid scintillator of an upper D1 module. The scattered neutron may then interact and deposit all or a portion of its energy in one of the lower D2 modules, providing the internal trigger signal necessary for a double scatter event. The energy of the scattered neutron is deduced from its time of flight from the upper to lower detector, which is summed with the energy measured for the recoil proton in the upper D1 module to obtain the energy of the incident solar neutron. The computed scatter angle of the neutron, as with gamma rays, yields an event circle on the sky, which can be further constrained since the true source of the detected neutrons is assumed to be the Sun."<ref name=Johnson>{{ cite web
|author=W. N. Johnson
|title=Appendix G to the NASA RESEARCH ANNOUNCEMENT for the COMPTON GAMMA RAY OBSERVATORY GUEST INVESTIGATOR PROGRAM
|publisher=National Aeronautics and Space Administration Goddard Space Flight Center
|location=Greenbelt, Maryland USA
|month=November
|year=1996
|url=http://heasarc.gsfc.nasa.gov/docs/cgro/nra/appendix_g.html#III.%20COMPTEL%20GUEST%20INVESTIGATOR%20PROGRAM
|pdf=
|accessdate=2013-04-05 }}</ref>
{{clear}}
=Electron telescopes=
[[Image:Galileo Energetic Particles Detector.jpg|thumb|right|200px|This is an image of the Energetic Particles Detector (EPD) aboard the Galileo Orbiter. Credit: NASA.]]
"[The] two bi-directional, solid-state detector telescopes [of the Galileo Orbiter are] mounted on a platform which [is] rotated by a stepper motor into one of eight positions. This rotation of the platform, combined with the spinning of the orbiter in a plane perpendicular to the platform rotation, [permits] a 4-pi [or 4π] steradian coverage of incoming [electrons]. The forward (0 degree) ends of the two telescopes [have] an unobstructed view over the [4π] sphere or [can] be positioned behind a shield which not only [prevents] the entrance of incoming radiation, but [contains] a source, thus allowing background corrections and in-flight calibrations to be made. ... The 0 degree end of the [Low-Energy Magnetospheric Measurements System] LEMMS [uses] magnetic deflection to separate incoming electrons and ions. The 180 degree end [uses] absorbers in combination with the detectors to provide measurements of higher-energy electrons ... The LEMMS [provides] measurements of electrons from 15 keV to greater than 11 MeV ... in 32 rate channels."<ref name=Williams>{{ cite web
|author=Donald J. Williams
|title=Energetic Particles Detector (EPD)
|publisher=NASA Goddard Space Flight Center
|location=Greenbelt, Maryland USA
|month=May 14,
|year=2012
|url=http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1989-084B-06
|pdf=
|accessdate=2012-08-11 }}</ref>
{{clear}}
=Positron telescopes=
[[Image:509305main GBM positron event 300dpi.jpg|thumb|right|200px|Observation of positrons from a terrestrial gamma ray flash is performed by the Fermi gamma ray telescope. Credit: NASA Goddard Space Flight Center.]]
The image at right contains a picture of the Fermi gamma-ray telescope that performed observations of positrons from their terrestrial gamma-ray flashes.
The positrons are not directly observed by the INTEGRAL space telescope, but "the 511 keV positron annihilation emission is".<ref name= Weidenspointner >{{ cite journal
|author=G. Weidenspointner, G.K. Skinner, P. Jean, J. Knödlseder, P. von Ballmoos, R. Diehl, A. Strong, B. Cordier, S. Schanne, C. Winkler
|title=Positron astronomy with SPI/INTEGRAL
|journal=New Astronomy Reviews
|month=October
|year=2008
|volume=52
|issue=7-10
|pages=454-6
|url=http://www.sciencedirect.com/science/article/pii/S1387647308001164
|arxiv=
|bibcode=
|doi=10.1016/j.newar.2008.06.019
|pmid=
|pdf=
|accessdate=2011-11-25 }}</ref>
{{clear}}
=Neutrino telescopes=
[[Image:Antares Neutrinoteleskop.jpg|thumb|right|250px|An artist illustration of the Antares neutrino detector and the [[w:Nautile|Nautile]]. Credit: .]]
[[Image:Icecube-architecture-diagram2009.PNG|thumb|left|200px|This is an architecture diagram of IceCube. Credit: [[w:User:Nasa-verve|Nasa-verve]].]]
"'''ANTARES''' [illustrated at right] is the name of a [[w:neutrino detector|neutrino detector]] residing 2.5 km under the [[w:Mediterranean Sea|Mediterranean Sea]] off the coast of Toulon, France. It is designed to be used as a directional ''Neutrino Telescope'' to locate and observe neutrino flux from cosmic origins in the direction of the [[w:Southern Hemisphere|Southern Hemisphere]] of the [[Earth]], a complement to the southern hemisphere neutrino detector [[w:IceCube|IceCube]] that detects neutrinos from the North."<ref name=ANTARESTelescope>{{ cite web
|title=ANTARES (telescope), In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 4,
|year=2012
|url=http://en.wikipedia.org/wiki/ANTARES_(telescope)
|accessdate=2012-08-23 }}</ref>
"The '''IceCube Neutrino Observatory''' (or simply '''IceCube''') [at left] is a [[w:neutrino telescope|neutrino telescope]] constructed at the [[w:Amundsen-Scott South Pole Station|Amundsen-Scott South Pole Station]] in [[w:Antarctica|Antarctica]].[1] Similar to its predecessor, the [[w:Antarctic Muon And Neutrino Detector Array|Antarctic Muon And Neutrino Detector Array]] (AMANDA)<!-- which relied on analog data transmission except for one digital development string -->, IceCube contains thousands of spherical optical sensors called Digital Optical Modules (DOMs), each with a [[w:photomultiplier tube|photomultiplier tube]] (PMT)<ref name=Abbasi>{{cite journal
|author=R. Abbasi ''et al.'' (IceCube Collaboration)
|year=2010
|title=Calibration and Characterization of the IceCube Photomultiplier Tube
|journal = Nuclear Instruments and Methods A
| volume = 618| pages= 139–152
| doi = 10.1016/j.nima.2010.03.102
|arxiv=1002.2442
|bibcode=2010NIMPA.618..139A }}</ref>
and a single board data acquisition computer which sends digital data to the counting house on the surface above the array.<ref name=Abbasi09>{{ cite journal
|author=R. Abbasi ''et al.'' (IceCube Collaboration)
|year=2009
|title=The IceCube Data Acquisition System: Signal Capture, Digitization, and Timestamping
|journal=Nuclear Instruments and Methods A
|volume=601 |pages=294–316
|doi=10.1016/j.nima.2009.01.001
|bibcode = 2009NIMPA.601..294T
|arxiv=0810.4930 }}</ref>
IceCube was completed on 18 December, 2010, New Zealand time.<ref>[http://icecube.wisc.edu/ IceCube Neutrino Observatory<!-- Bot generated title -->]</ref>"<ref name=IceCubeNeutrinoObservatory>{{ cite web
|title=IceCube Neutrino Observatory, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 10,
|year=2012
|url=http://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory
|accessdate=2012-08-23 }}</ref>
{{clear}}
=Gamma-ray telescopes=
[[Image:Comptel.gif|thumb|left|200px|The Imaging Compton Telescope (COMPTEL) utilizes the Compton Effect and two layers of gamma-ray detectors. Credit: NASA.]]
[[Image:GLAST on the payload attach fitting.jpg|thumb|right|200px|The Fermi Gamma-ray Space Telescope sits on its payload attachment fitting. Credit: NASA/Kim Shiflett.]]
"The '''Imaging Compton Telescope''', ('''COMPTEL''') by the [[w:Max Planck Institute for Extraterrestrial Physics|Max Planck Institute for Extraterrestrial Physics]], the [[w:University of New Hampshire|University of New Hampshire]], [[w:Netherlands Institute for Space Research|Netherlands Institute for Space Research]], and ESA's Astrophysics Division was tuned to the 0.75-30 MeV energy range and determined the angle of arrival of photons to within a degree and the energy to within five percent at higher energies. The instrument had a field of view of one [[w:steradian|steradian]]. For cosmic gamma-ray events, the experiment required two nearly simultaneous interactions, in a set of front and rear scintillators. Gamma rays would [[w:Compton scattering|Compton scatter]] in a forward detector module, where the interaction energy ''E<sub>1</sub>'', given to the recoil electron was measured, while the Compton scattered photon would then be caught in one of a second layer of scintillators to the rear, where its total energy, ''E<sub>2</sub>'', would be measured. From these two energies, ''E<sub>1</sub>'' and ''E<sub>2</sub>'', the Compton scattering angle, angle θ, can be determined, along with the total energy, ''E<sub>1</sub> + E<sub>2</sub>'', of the incident photon. The positions of the interactions, in both the front and rear scintillators, was also measured. The [[w:Euclidean vector|vector]], '''V''', connecting the two interaction points determined a direction to the sky, and the angle θ about this direction, defined a cone about '''V''' on which the source of the photon must lie, and a corresponding "event circle" on the sky."<ref name=ComptonGammaRayObservatory>{{ cite journal
|title=Compton Gamma Ray Observatory
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 26,
|year=2013
|url=http://en.wikipedia.org/wiki/Compton_Gamma_Ray_Observatory
|pdf=
|accessdate=2013-04-05 }}</ref>
"COMPTEL's upper layer of detectors are filled with a liquid scintillator which scatters an incoming gamma-ray photon according to the Compton Effect. This photon is then absorbed by NaI crystals in the lower detectors. The instrument records the time, location, and energy of the events in each layer of detectors which makes it possible to determine the direction and energy of the original gamma-ray photon and reconstruct an image and energy spectrum of the source."<ref name=Gehrels>{{ cite web
|author=Neil Gehrels
|title=The Imaging Compton Telescope (COMPTEL)
|publisher=NASA Goddard Space Flight Center
|location=Greenbelt, Maryland USA
|month=August 1,
|year=2005
|url=http://heasarc.gsfc.nasa.gov/docs/cgro/cgro/comptel.html
|pdf=
|accessdate=2013-04-05 }}</ref>
"The Large Area Telescope (LAT) [of the [[w:Fermi Gamma-ray Space Telescope|Fermi Gamma-ray Space Telescope]] ] detects individual gamma rays using technology similar to that used in terrestrial [[w:particle accelerator|particle accelerator]]s. [[w:Photons|Photons]] hit thin metal sheets, converting to electron-positron pairs, via a process known as [[w:pair production|pair production]]. These charged particles pass through interleaved layers of silicon [[w:microstrip detector|microstrip detector]]s, causing [[w:ionization|ionization]] which produce detectable tiny pulses of electric charge. Researchers can combine information from several layers of this tracker to determine the path of the particles. After passing through the tracker, the particles enter the [[w:calorimeter|calorimeter]], which consists of a stack of [[w:caesium iodide|caesium iodide]] [[w:scintillator|scintillator]] crystals to measure the total energy of the particles. The LAT's field of view is large, about 20% of the sky. The resolution of its images is modest by astronomical standards, a few arc minutes for the highest-energy photons and about 3 degrees at 100 MeV. The LAT is a bigger and better successor to the [[w:EGRET (telescope)|EGRET]] instrument on NASA's [[w:Compton Gamma Ray Observatory|Compton Gamma Ray Observatory]] satellite in the 1990s."<ref name=FermiTelescope>{{ cite journal
|title=Fermi Gamma-ray Space Telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 9,
|year=2012
|url=http://en.wikipedia.org/wiki/Fermi_Gamma-ray_Space_Telescope
|pdf=
|accessdate=2012-06-10 }}</ref>
"For X-rays, the index of refraction is defined by Rayleigh scattering,"<ref name=Wogan>{{ cite web
|author=Tim Wogan
|title=Silicon 'prism' bends gamma rays
|publisher=Institute of Physics
|location=
|month=May 9,
|year=2012
|url=http://physicsworld.com/cws/article/news/2012/may/09/silicon-prism-bends-gamma-rays
|pdf=
|accessdate=2013-05-09 }}</ref> especially in the use of Wolter telescopes.
"[T]he strength of the effect drops off as the inverse square of the X-ray energy. This means that at high X-ray energies – and on into low gamma-ray energies – the radiation is not bent enough for a lens to work effectively."<ref name=Wogan/>
"[T]he index of refraction starts to make a comeback at energies greater than about 700 keV. What is more, while the index of refraction is negative for X-rays, it becomes positive for gamma rays."<ref name=Wogan/>
"What is new now is that with gamma rays we can really address the extremely high electric field of the nucleus," with Delbrück scattering.<ref name=Habs>{{ cite web
|author=Dietrich Habs
|title=Silicon 'prism' bends gamma rays
|publisher=Institute of Physics
|location=
|month=May 9,
|year=2012
|url=http://physicsworld.com/cws/article/news/2012/may/09/silicon-prism-bends-gamma-rays
|pdf=
|accessdate=2013-05-09 }}</ref>
"The measurements indicate that there exists an index of refraction for gamma-ray energies that is substantially larger than people believed before".<ref name=Pietralla>{{ cite web
|author=Norbert Pietralla
|title=Silicon 'prism' bends gamma rays
|publisher=Institute of Physics
|location=
|month=May 9,
|year=2012
|url=http://physicsworld.com/cws/article/news/2012/may/09/silicon-prism-bends-gamma-rays
|pdf=
|accessdate=2013-05-09 }}</ref>
"Materials with nuclei that have a large positive charge – such as gold – should be ideal for making gamma-ray lenses".<ref name=Wogan/>
{{clear}}
=X-ray telescopes=
[[Image:Xrtlayout.gif|thumb|right|200px|The XRT uses a grazing incidence Wolter 1 telescope to focus X-rays onto a state-of-the-art CCD. Credit: .]]
"X-ray telescopes can use a variety of different designs to image X-rays. The most common methods used in X-ray telescopes are grazing incidence mirrors and coded apertures. The limitations of X-ray optics result in much narrower fields of view than visible or UV telescopes."<ref name=Xraytelescope>{{ cite journal
|title=X-ray telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 17,
|year=2012
|url=http://en.wikipedia.org/wiki/X-ray_telescope
|pdf=
|accessdate=2012-06-15 }}</ref>
An extreme example of a reflecting telescope is demonstrated by the grazing incidence X-ray telescope (XRT) of the [[w:Swift Gamma-Ray Burst Mission|Swift]] satellite that focuses X-rays onto a state-of-the-art charge-coupled device (CCD), in red at the focal point of the grazing incidence mirrors (in black at the right).
"A '''Wolter telescope''' is a telescope for X-rays using only grazing incidence optics. ... X-rays mirrors can be built, but only if the angle from the plane of reflection is very low (typically 10 arc-minutes to 2 degrees)<ref name="Pal Singh, 2005" >{{cite web
|url=http://www.ias.ac.in/resonance/June2005/pdf/June2005p15-23.pdf
|author=Kulinder Pal Singh
|title=Techniques in X-ray Astronomy
|format=pdf
|archiveurl=http://web.archive.org/web/20120919153449/http://www.ias.ac.in/resonance/June2005/pdf/June2005p15-23.pdf|archivedate=2012-09-19}}</ref>. These are called ''glancing (or grazing) incidence mirrors''. In 1952, Hans Wolter outlined three ways a telescope could be built using only this kind of mirror.<ref name=WolerGIM>{{ cite journal
|title=Glancing Incidence Mirror Systems as Imaging Optics for X-rays
|author=Hans Wolter
|journal=Ann. Physik
|volume=10
|pages=94
|year=1952
|ref=Wolter, Glancing Incidence Mirror Systems, 1952
}}</ref><ref name=WolterGMS>{{ cite journal
|title=A Generalized Schwarschild Mirror Systems For Use at Glancing Incidence for X-ray Imaging
|author=Hans Wolter
|journal=Ann. Physik
|volume=10
|pages=286
|year=1952
|ref=Wolter, Generalized Schwarschild Mirror System, 1952
}}</ref>. Not surprisingly, these are called Wolter telescopes of type I, II, and III. Each has different advantages and disadvantages.<ref name=Petre>{{ cite web
|author=Rob Petre
|url=http://imagine.gsfc.nasa.gov/docs/science/how_l2/xtelescopes_systems.html
|title=X-ray Imaging Systems
|publisher=NASA
|ref=Petre, X-ray Imaging Systems }}</ref>"<ref name=Woltertelescope>{{ cite journal
|title=Wolter telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 20,
|year=2012
|url=http://en.wikipedia.org/wiki/Wolter_telescope
|pdf=
|accessdate=2012-06-15 }}</ref>
=Optical telescopes=
[[Image:HST-SM4.jpeg|thumb|right|200px|The Hubble Space Telescope is seen from the departing Space Shuttle Atlantis, flying Servicing Mission 4 (STS-125), the fifth and final human spaceflight to visit the observatory. Credit: Ruffnax (Crew of STS-125).]]
[[Image:HaleTelescope-MountPalomar.jpg|thumb|left|200px|Mt.Palomar's 200-inch Telescope, pointing to the zenith, is seen from the east side. Note the person standing below the telescope (center-right at the bottom of the image). Credit: NASA.]]
'''Def.''' "[a] [[wikt:monocular|monocular]] [[wikt:optical|optical]] [[wikt:instrument|instrument]] possessing [[wikt:magnification|magnification]] for observing distant objects", per Wiktionary [[wikt:telescope|telescope]], is called a '''telescope'''.
The [[w:Hubble Space Telescope|Hubble Space Telescope]] (HST) is an excellent example of a [[Radiation satellites|radiation astronomy satellite]] designed for more than one purpose: the various astronomies of [[optical astronomy]].
The HST is an optical astronomy telescope that “incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest."<ref name=HubbleSpaceTelescope>{{ cite journal
|title=Hubble Space Telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=January 21,
|year=2013
|url=http://en.wikipedia.org/wiki/Hubble_Space_Telescope
|accessdate=2013-01-22 }}</ref>
Most radiation telescopes, especially optical telescopes, combine a variety of lenses, mirrors, active and adaptive optics, filters, detectors, mounts, image processing, and observatories, in many locations.
{{clear}}
=Active optics=
[[Image:GTC Active Optics Acutators.jpg|thumb|right|200px|Actuators are part of the active optics of the ''[[w:Gran Telescopio Canarias|Gran Telescopio Canarias]]''. Credit: .]]
“'''Active optics''' is a [[w:technology|technology]] used with [[w:reflecting telescope|reflecting telescope]]s developed in the 1980s<ref name=Hardy>{{ cite journal
|author=John W. Hardy
|title=Active optics: A new technology for the control of light
|year=1977
|month=June
|series=Proceedings of the IEEE
|pages=110
|url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA339170
|bibcode=1978IEEEP..66..651H }}</ref>, which actively shapes a telescope's [[w:mirror|mirror]]s to prevent deformation due to external influences such as wind, temperature, mechanical stress. Without active optics, the construction of 8 metre class telescopes is not possible, nor would telescopes with segmented mirrors be feasible.” from the Wikipedia article on [[w:Active optics|active optics]].
“[T]elescopes built since the 1980s use very thin mirrors ... which are too thin to keep themselves rigidly in the correct shape. Instead, an array of [[w:actuator|actuator]]s behind the mirror keeps it in an optimal shape. The telescope may also be segmented into many small mirrors, preventing most of the gravitational distortion that occurs in large, thick mirrors. The combination of actuators, a quality-of-image [[w:detector|detector]], and a real-time computer program to move the actuators to obtain the best possible image is termed ''active optics''. The name ''active'' optics means that the system keeps a mirror (usually the primary) in its optimal shape against all environmental factors such as [[w:gravity|gravity]] (at different telescope inclinations), wind, temperature changes, telescope axis deformation, et cetera. Active optics correct all factors that may affect image quality at timescales of one second or more. The telescope is therefore ''actively'' still, in its optimal shape.” after the Wikipedia article on [[w:Active optics|active optics]].
{{clear}}
=Adaptive optics=
[[Image:GRAAL instrument.jpg|thumb|right|200px|This image shows some of the GRAAL instrument team inspecting GRAAL’s mechanical assembly. Credit: ESO.]]
'''Def.''' "[a]n optical system in telescopes that reduces atmospheric distortion by dynamically measuring and correcting wavefront aberrations in real time, often by using a deformable mirror", from Wiktionary [[wikt:adaptive optics|adaptive optics]], is called '''adaptive optics'''.
"Already it has allowed ground-based telescopes to produce images with sharpness rivalling those from the Hubble Space Telescope. The technique is expected to revolutionize the future of ground-based optical astronomy."<ref name=Roddier>{{ cite book
|author=
|title=Adaptive Optics in Astronomy
|publisher=Cambridge University Press
|location=Cambridge, United Kingdom
|month=
|year=1999
|editor=François Roddier
|pages=411
|url=http://books.google.com/books?hl=en&lr=&id=4n5tBN21LRsC&oi=fnd&pg=PP1&ots=7FUaBW-y4B&sig=1NLsHH3qkTKN4yA4dD1C5YqxZhg
|arxiv=
|bibcode=
|doi=
|pmid=
|isbn=0 521 55375 X
|pdf=http://catdir.loc.gov/catdir/samples/cam031/00500597.pdf
|accessdate=2012-02-15 }}</ref>
At right is an image of the adaptive optics of the GRAAL. GRAAL stands for GRound layer Adaptive optics Assisted by Lasers. It will use the technique of adaptive optics to improve the quality of images by compensating for turbulence in the lower layers of the atmosphere, up to an altitude of 1 kilometre. GRAAL, which will be installed on ESO’s Very Large Telescope (VLT) on Cerro Paranal in Chile, is designed to improve the vision of the VLT’s already excellent HAWK-I camera even further. Currently, HAWK-I operates without adaptive optics. Installing GRAAL will improve the sharpness of HAWK-I’s images, and reduce the exposure times needed by up to a factor of two.
{{clear}}
=Refracting Telescopes=
[[Image:Kepschem.png|thumb|right|200px|This is a schematic of a Keplerian refracting telescope which uses two different sizes of planoconvex lenses. Credit: .]]
From the Wikipedia article [[w:|Refracting telescope]]: "The '''Keplerian Telescope''', invented by [[w:Johannes Kepler|Johannes Kepler]] in 1611, is an improvement on Galileo's design.<ref name=Tunnacliffe>{{ cite book
|title= Optics
|author= AH Tunnacliffe, JG Hirst
|year= 1996
|publisher=
|location= Kent, England
|isbn= 0-900099-15-1
|pages= 233–7
|url= }}</ref> It uses a [plano]convex lens as the eyepiece instead of Galileo's [double] concave one. The advantage of this arrangement is [that] the rays of light emerging from the eyepiece are converging. This allows for a much wider [[w:field of view|field of view]] and greater eye relief but the image for the viewer is inverted. Considerably higher magnifications can be reached with this design but to overcome [[w:Optical aberration|aberration]]s the simple objective lens needs to have a very high [[w:Focal ratio|f-ratio]]"<ref name=RefractingTelescope>{{ cite journal
|title=Refracting telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 7,
|year=2012
|url=http://en.wikipedia.org/wiki/Refracting_telescope
|pdf=
|accessdate=2012-07-07 }}</ref>.
"All refracting telescopes use the same principles. The combination of an [[w:objective (optics)|objective]] [[w:lens (optics)|lens]] '''1''' and some type of [[w:eyepiece|eyepiece]] '''2''' is used to gather more light than the human eye could collect on its own, focus it '''5''', and present the viewer with a [[w:brightness|brighter]], [[w:clarity|clearer]], and [[w:magnification|magnified]] [[w:virtual image|virtual image]] '''6'''."<ref name=RefractingTelescope/>
{{clear}}
=Reflecting telescopes=
[[Image:SOFIA 2.5M Primary Mirror.jpg|thumb|left|200px|The [[NASA]] logo on Bldg. 703 at the Dryden Aircraft Operations Facility in Palmdale, California, is reflected in the 2.5 m primary mirror of the SOFIA observatory's telescope. Credit: .]]
[[Image:Franklin reflector 24.jpg|right|thumb|200px|24 inch convertible Newtonian/Cassegrain reflecting telescopeis shown on display at the [[w:Franklin Institute|Franklin Institute]]. Credit: .]]
"A '''reflecting telescope''' (also called a '''reflector''') is an [[w:optical telescope|optical telescope]] which uses a single or combination of [[w:curved mirror|curved mirror]]s that reflect [[w:light|light]] and form an [[w:image|image]]."<ref name=ReflectingTelescope>{{ cite journal
|title=Reflecting telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 2,
|year=2012
|url=http://en.wikipedia.org/wiki/Reflecting_telescope
|pdf=
|accessdate=2012-07-07 }}</ref>
{{clear}}
=Catadioptric telescopes=
'''Def.''' “optical systems that employ both refractive (dioptric) and reflective (catoptric) elements”, after Wiktionary [[wikt:catadioptric|catadioptric]], are called '''catadioptric optical systems'''.
'''Def.''' “[t]he construction and use of catadioptric lenses and systems”, from Wiktionary [[wikt:catadioptrics|catadioptrics]], is called '''catadioptrics'''.
=Dobsonian telescopes=
[[Image:Red dobsonian.jpg|thumb|right|200px|This is a red Dobsonian telescope on display at Stellafane in the early 1980s. Credit: .]]
"A '''Dobsonian telescope''' is an alt-azimuth mounted newtonian telescope design popularized by the [amateur astronomy] John Dobson starting in the 1960s. Dobson's telescopes featured a simplified mechanical design that was easy to manufacture from readily available components to create a large, portable, low-cost telescope. The design is optimized for visually observing faint deep sky objects such as nebulae. This type of observation requires a large objective diameter (i.e. light-gathering power) of relatively short focal length and portability for travel to relatively less light polluted locations.<ref name="books.google.com">[http://books.google.com/books?id=l2TNnHkdDpkC&pg=PA286&lr=#PPA287,M1 Jack Newton, Philip Teece - "'''The Guide to Amateur Astronomy'''" - Page 287]</ref><ref>[http://books.google.com/books?id=9gUjaCMlX5oC&pg=PA37&dq=dobsonian+amateur+telescope+makers&lr= Timothy Ferris "'''Seeing in the Dark'''" - Page 39]</ref>"<ref name=DobsonianTelescope>{{ cite web
|title=Dobsonian telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 20,
|year=2013
|url=https://en.wikipedia.org/wiki/Dobsonian_telescope
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Schmidt telescopes=
[[Image:Schmidt telescope (PSF).svg|thumb|200px|right|The diagram illustrates the optical ray paths inside a Schmidt telescope. Credit: .]]
[[Image:Alfred-Jensch-Teleskop.jpg|thumb|200px|left|The 2 meter diameter (Alfred-Jensch-Telescope at the Karl Schwarzschild Observatory in Tautenburg, Thuringia, Germany, is the largest '''Schmidt camera''' in the world. Credit: .]]
At the top of this lecture/article is the Schmidt Telescope at the former Brorfelde Observatory. It is now used by amateur astronomers. The telescope from 1966 is still located in the same building in Brorfelde as originally. Today the telescope has a 77 cm mirror and a digital 2048x2048 pixel CCD-camera. Originally photographic film was used, and in the lower right part an engineer is showing the former film-box, which was then placed behind the locker at the center of the telescope (at the prime focus).
"A '''Schmidt camera''', also referred to as the '''Schmidt telescope''', is a catadioptric astrophotographic [optical] telescope designed to provide wide fields of view with limited aberrations."<ref name=SchmidtCamera>{{ cite web
|title=Schmidt camera, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 30,
|year=2013
|url=https://en.wikipedia.org/wiki/Schmidt_camera
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Maksutov telescopes=
[[Image:Maksutov 150mm.jpg|right|thumb|200px|A 150mm aperture Maksutov–Cassegrain telescope is shown. Credit: .]]
[[Image:Maksutov spot cassegrain.png|right|thumb|200px|Light path in a typical "Gregory" or "spot" Maksutov–Cassegrain is diagrammed. Credit: .]]
"The '''Maksutov''' is a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly "spherically symmetrical".<ref name=Savard>{{ cite web
|author=John J. G. Savard
|title='Miscellaneous Musings
|url=http://www.quadibloc.com/science/opt0203.htm }}</ref> The negative lens is usually full diameter and placed at the entrance pupil of the telescope (commonly called a "corrector plate" or "meniscus corrector shell"). The design corrects the problems of off-axis aberrations such as coma found in reflecting telescopes while also correcting chromatic aberration."<ref name=MaksutovTelescope>{{ cite web
|title=Maksutov telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 9,
|year=2013
|url=https://en.wikipedia.org/wiki/Maksutov_telescope
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Ultraviolet telescopes=
"The Extreme ultraviolet Imaging Telescope (EIT) is an instrument on the [[w:Solar and Heliospheric Observatory|SOHO]] spacecraft used to obtain high-resolution images of the solar corona in the ultraviolet range. The EIT instrument is sensitive to light of four different wavelengths: 17.1, 19.5, 28.4, and 30.4 nm, corresponding to light produced by highly ionized iron (XI)/(X), (XII), (XV), and helium (II), respectively. EIT is built as a single telescope with a quadrant structure to the entrance mirrors: each quadrant reflects a different colour of EUV light, and the wavelength to be observed is selected by a shutter that blocks light from all but the desired quadrant of the main telescope."<ref name=ExtremeUltravioletImagingTelescope>{{ cite journal
|title=Extreme ultraviolet Imaging Telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 28,
|year=2012
|url=http://en.wikipedia.org/wiki/Extreme_ultraviolet_Imaging_Telescope
|pdf=
|accessdate=2013-07-24 }}</ref>
"EIT is the first long-duration instrument to use normal incidence multilayer coated optics to image the Sun in extreme ultraviolet. This portion of the spectrum is extremely difficult to reflect, as most matter absorbs the light very strongly. Conventionally these wavelengths have been reflected either using grazing incidence (as in a Wolter telescope for imaging X-rays) or a diffraction grating (as ... flown on Skylab in the mid 1970s)."<ref name=ExtremeUltravioletImagingTelescope/>
"[V]acuum deposition technology allows mirrors to be coated with extremely thin layers of nearly any material. The multilayer mirrors in an EUV telescope are coated with alternate layers of a light "spacer" element (such as silicon) that absorbs EUV light only weakly, and a heavy "scatterer" element (such as molybdenum) that absorbs EUV light very strongly. Perhaps 100 layers of each type might be placed on the mirror, with a thickness of around 10 nm each. The layer thickness is tightly controlled, so that at the desired wavelength, reflected photons from each layer interfere constructively. In this way, reflectivities of up to ~50% can be attained."<ref name=ExtremeUltravioletImagingTelescope/>
"The multilayer technology allows conventional telescope forms (such as the Cassegrain or Ritchey-Chretien designs) to be used in a novel part of the spectrum."<ref name=ExtremeUltravioletImagingTelescope/>
=Visual telescopes=
[[Image:USNO Refractor 1904.jpg|thumb|right|200px|This image shows the 26-inch Warner & Swasey refracting telescope at the United States Naval Observatory. Credit: Waldon Fawcett.]]
“I think everyone can conjure up a mental image of astronomers at every level and place in history, gazing through the eyepieces of their telescopes at sights far away - true visual astronomy.”<ref name=Cooke>{{ cite book
|author=Antony Cooke
|title=Visual Astronomy Under Dark Skies: A New Approach to Observing Deep Space
|publisher=Springer-Verlag
|location=London
|month=
|year=2005
|editor=
|pages=180
|url=http://books.google.com/books?id=SXmrBfl4H3sC&dq=entity+astronomy&lr=&source=gbs_navlinks_s
|bibcode=
|doi=
|pmid=
|isbn=1852339012
|pdf=
|accessdate=2011-11-06 }}</ref>
{{clear}}
=Astronomical filters=
[[Image:Dichroic filters.jpg|thumb|right|200px|[[w:Ultraviolet|Ultraviolet]] filters are used in astronomy for blocking this part of the spectrum, which causes the camera to heat up when photographing without affecting the image. Credit: .]]
“An '''astronomical filter''' is sometimes a [[w:telescope|telescope]] accessory used ... to simply enhance the details of [[w:celestial objects|celestial objects]] ... [or as part of the photometric system of] [[w:Photometric_system#Filters_Used|filters]] ... to understand the [[astrophysics]] (such as [[w:stellar classification|stellar classification]] and placement of a [[w:celestial body|celestial body]] on its [[w:Wien%27s_displacement_law|Wein Curve]]), occurring for the object in a given [[w:Photometric_system|bandpass]] via [[w:Photometry_(astronomy)|photometry]].”<ref name=AstronomicalFilter/>
“Most astronomical filters work by blocking a specific part of the color spectrum above and below a ''bandpass'', significantly increasing the signal to noise of the [interesting] wavelengths, and so making the object more visible, 'contrasty', or defined. While ... color filters transmit certain colors from the spectrum and are usually used for observation of the [[w:planets|planets]] and the [[Moon]], ... polarizing filters work by adjusting the brightness, and are usually used for the Moon. The broadband and narrowband filters transmit the wavelengths that are emitted by ... [[w:Hydrogen|hydrogen]] and [[w:Oxygen|oxygen]] atoms, and are frequently used for reducing [[w:light pollution|light pollution]].[1]”<ref name=AstronomicalFilter>{{ cite journal
|title=Astronomical filter
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 18,
|year=2012
|url=http://en.wikipedia.org/wiki/Astronomical_filter
|pdf=
|accessdate=2012-07-29 }}</ref>
=Infrared telescopes=
[[Image:Spitzer- Telescopio.jpg|thumb|right|200px|The image shows the Spitzer Space Telescope prior to launch. Credit: NASA/JPL/Caltech.]]
[[Image:Diagram Reflector RitcheyChretien.svg|thumb|right|200px|The diagram is of a Ritchey-Chrétien reflector telescope. Credit: .]]
[[Image:NOFS 40inch03.jpg|thumb|left|200px|This is an early Ritchey-Chrétien reflector telescope. Credit: P. Shankland.]]
The Spitzer telescope is a "Ritchey–Chrétien telescope ... a specialized Cassegrain telescope ... that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate optical errors (coma). They have [a] large field of view free of optical errors compared to a more conventional reflecting telescope configuration."<ref name=RitcheyChretienTelescope>{{ cite journal
|title=Ritchey–Chrétien telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 22,
|year=2013
|url=http://en.wikipedia.org/wiki/Ritchey–Chrétien_telescope
|pdf=
|accessdate=2013-07-24 }}</ref>
"The [[w:radius of curvature (optics)|radii of curvature]] of the primary and secondary mirrors, respectively, in a two-mirror Cassegrain configuration are
:<math>R_1 = -\frac{2DF}{F - B}</math>
and
:<math>R_2 = -\frac{2DB}{F - B - D}</math>
where
* <math>F</math> is the effective [[w:focal length|focal length]] of the system,
* <math>B</math> is the back focal length (the distance from the secondary to the focus), and
* <math>D</math> is the distance between the two mirrors."<ref name=RitcheyChretienTelescope/>
"If, instead of <math>B</math> and <math>D</math>, the known quantities are the focal length of the primary mirror, <math>f_1</math>, and the distance to the focus behind the primary mirror, <math>b</math>, then <math>D = f_1(F - b)/(F + f_1)</math> and <math>B = D + b</math>."<ref name=RitcheyChretienTelescope/>
"For a Ritchey–Chrétien system, the [[w:conic constant|conic constant]]s <math>K_1</math> and <math>K_2</math> of the two mirrors are chosen so as to eliminate third-order spherical aberration and coma; the solution is
:<math>K_1 = -1 - \frac{2}{M^3}\cdot\frac{B}{D}</math>
and
:<math>K_2 = -1 - \frac{2}{(M - 1)^3}\left[M(2M - 1) + \frac{B}{D}\right]</math>
where <math>M = F/f_1 = (F - B)/D</math> is the secondary magnification.<ref name=Smith>{{ cite book
|author=Warren J. Smith
|year=2008
|title=Modern Optical Engineering
|pages=508–10
|edition=4th
|publisher=McGraw-Hill Professional
|isbn=978-0-07-147687-4 }}</ref> Note that <math>K_1</math> and <math>K_2</math> are less than <math>-1</math> (since <math>M>1</math>), so both mirrors are hyperbolic. (The primary mirror is typically quite close to being parabolic, however.)"<ref name=RitcheyChretienTelescope/>
"The hyperbolic curvatures are difficult to test, especially with equipment typically available to amateur telescope makers or laboratory-scale fabricators; thus, older telescope layouts predominate in these applications. However, professional optics fabricators and large research groups test their mirrors with [[w:interferometer|interferometer]]s. A Ritchey–Chrétien then requires minimal additional equipment, typically a small optical device called a [[w:null corrector|null corrector]] that makes the hyperbolic primary look spherical for the interferometric test."<ref name=RitcheyChretienTelescope/>
The telescope at left is the early Ritchey–Chrétien 1.0 meter telescope at NOFS at the [[w:United States Naval Observatory Flagstaff Station|United States Naval Observatory Flagstaff Station]].
=Submillimeter telescopes=
[[Image:Caltech-Submillimeter-Observatory (straightened).jpg|thumb|right|200px|This photograph shows the 10.4-metre diameter submillimeter wavelength telescope of the Caltech Submillimeter Observatory (CSO). Credit: [http://www.flickr.com/people/62472689@N00 Samuel Bouchard] from Quebec City, Canada; modified by [[commons:User:Huntster|Huntster]].]]
[[Image:Four antennas ALMA.jpg|thumb|left|200px|Four antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) gaze up at the star-filled night sky. Credit: ESO/José Francisco Salgado (josefrancisco.org).]]
[[Image:SMT 1.png|thumb|right|200px|The [[w:Heinrich Hertz Submillimeter Telescope|Heinrich Hertz Submillimeter Telescope]] is shown at night. Credit: [[w:User:Geremia|Geremia]].]]
The [[w:Atacama Large Millimeter Array|Atacama Large Millimeter/submillimeter Array]] (ALMA) is being constructed at an altitude of 5000 m on the [[w:Chajnantor plateau|Chajnantor plateau]] in the [[w:Atacama Desert|Atacama Desert]] of [[w:Chile|Chile]]. This is one of the driest places on [[Earth]] and this dryness, combined with the thin atmosphere at high altitude, offers superb conditions for observing the Universe at millimetre and submillimetre wavelengths. At these long wavelengths, astronomers can probe, for example, [[w:Molecular cloud|molecular cloud]]s, which are dense regions of gas and dust where new stars are born when a cloud collapses under its own gravity. Currently, the Universe remains relatively unexplored at submillimetre wavelengths, so astronomers expect to uncover many new secrets about star formation, as well as the origins of galaxies and planets.
"ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011. The array has been fully operational since March 2013.<ref name=Alma>{{ cite web
|title=Alma telescope: Ribbon cut on astronomical giant
|url=http://www.bbc.co.uk/news/science-environment-21774448
|publisher=BBC
|accessdate=13 March 2013 }}</ref>"<ref name=AtacamaLargeMillimeterArray>{{ cite web
|title=Atacama Large Millimeter Array, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 8,
|year=2013
|url=http://en.wikipedia.org/wiki/Atacama_Large_Millimeter_Array
|accessdate=2013-07-21 }}</ref>
“The '''Submillimeter Telescope''' ('''SMT'''), formerly known as the '''Heinrich Hertz Submillimeter Telescope''' [at lower right], is a [[w:submillimetre astronomy|submillimeter wavelength]] [[w:radio telescope|radio telescope]] located on [[w:Mount Graham|Mount Graham]], [[w:Arizona|Arizona]]. It is a 10-meter-wide parabolic dish inside a building to protect it from bad weather. The building front doors and roof are opened when the telescope is in use. ... The dryness of the air around and above Mt. Graham is particulatly vital for [[w:Extremely high frequency|EHF]] (extremely low wavelength radio) and far-[[w:infrared|infrared]] observations - a region of the [[w:electromagnetic spectrum|spectrum]] where the [[w:electromagnetic wave|electromagnetic wave]]s are strongly [[w:attenuation|attenuated]] by any [[w:water vapor|water vapor]] or clouds in the air.”<ref name=HeinrichHertzSubmillimeterTelescope>{{ cite journal
|title=Heinrich Hertz Submillimeter Telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 5,
|year=2012
|url=http://en.wikipedia.org/wiki/Heinrich_Hertz_Submillimeter_Telescope
|pdf=
|accessdate=2012-08-04 }}</ref>
{{clear}}
=Radio telescopes=
[[Image:parkes.arp.750pix.jpg|thumb|right|200px|This 64 meter radio telescope is at [[w:Parkes Observatory|Parkes Observatory]] Credit: John Sarkissian (CSIRO Parkes Observatory).]]
'''Def.''' “[a] device for observing astronomical sources of radio waves”, after Wiktionary [[wikt:radio telescope|radio telescope]], is called a '''radio telescope'''.
“A '''radio telescope''' is a form of [[w:Directional antennae|directional]] [[radio]] [[w:Antenna (radio)|antenna]], [as] used in tracking and collecting data from [[w:satellite|satellite]]s and [[w:space probe|space probe]]s ... that [operates] in the [[w:radio frequency|radio frequency]] portion of the [[w:electromagnetic spectrum|electromagnetic spectrum]] ... Radio telescopes are typically large [[w:Parabolic antenna|parabolic]] ("dish") antennas used singly or in an array. Radio [[w:observatory|observatories]] are preferentially located far from major centers of population to avoid [[w:electromagnetic interference|electromagnetic interference]] (EMI) from radio, [[w:TV|TV]], [[w:radar|radar]], and other EMI emitting devices.” from the Wikipedia entry about the [[w:Radio telescope|radio telescope]].
{{clear}}
=Microwave telescopes=
[[Image:RTEmagicC Planck satellite 01.jpg|thumb|right|200px|The Planck telescope was launched in 2009 to observe the Cosmic Microwave Background Radiation. Credit: ESA.]]
"The basic scientific goal of the Planck mission is to measure [cosmic microwave background] CMB anisotropies at all angular scales larger than 10 arcminutes over the entire sky with a precision of ~2 parts per million. The model payload consists of a 1.5 meter off-axis telescope with two focal plane arrays of detectors sharing the focal plane. Low frequencies will be covered by 56 tuned radio receivers sensitive to 30-100 GHz, while high frequencies will be covered by 56 bolometers sensitive to 100-850 GHz."<ref name=Chuss>{{ cite web
|author=David T. Chuss
|title=The Planck Mission
|publisher=Goddard Space Flight Center
|location=Greenbelt, Maryland USA
|month=April 18,
|year=2008
|url=http://lambda.gsfc.nasa.gov/product/space/p_overview.cfm
|accessdate=2013-12-12 }}</ref>
{{clear}}
=Radar telescopes=
[[Image:ADU-1000-3.jpg|thumb|200px|right|This image shows the early planetary radar at [[w:Pluton (complex)|Pluton]], USSR, 1960. Credit: [[commons:User:Rumlin|Rumlin]].]]
[[Image:Arecibo Observatory Aerial View.jpg|thumb|left|200px|The Arecibo Radio Telescope, Arecibo, Puerto Rico, at 1000 feet (305 m) across, is the largest dish antenna in the world. Credit: H. Schweiker/WIYN and NOAO/AURA/NSF, NOAA.]]
[[Image:Evpatori.jpg|thumb|200px|left|The image is of the Evpatoria RT-70 radar telescope in the Ukraine. Credit: Bebo.]]
[[Image:20100621 TanDEM-X download.jpg|thumb|right|200px|In this artist's impression TerraSAR-X and TanDEM-X are in orbit. Credit: Astrium GmbH.]]
The image at right shows planetary radar telescopes at [[w:Pluton (complex)|Pluton]], USSR, in 1960.
The "Arecibo Observatory in Puerto Rico [is] the world's largest, and most sensitive, single-dish radio telescope."<ref name=Brand>{{ cite web
| author=David Brand
| title=Astrophysicist Robert Brown, leader in telescope development, named to head NAIC and its main facility, Arecibo Observatory
| publisher=Cornell University
| date=21 January 2003
| url=http://www.news.cornell.edu/releases/Jan03/NAIC.director.deb.html
| accessdate=2008-09-02 }}</ref>
"The 1,000-foot-diameter (305 meters) Arecibo telescope [... provides] access to state-of-the-art observing for scientists in [[radio astronomy]], solar system radar and [[Atmospheric astronomy|atmospheric studies]], and the observatory has the unique capability for solar system and ionosphere (the atmosphere's ionized upper layers) radar remote sensing."<ref name=Brand/>
"The telescope has three radar transmitters, with [[w:EIRP|effective isotropic radiated powers]] of 20 TW at 2380 MHz, 2.5 TW (pulse peak) at 430 MHz, and 300 MW at 47 MHz. The telescope is a [[w:spherical reflector|spherical reflector]], not a [[w:parabolic reflector|parabolic reflector]]. To aim the telescope, the receiver is moved to intercept signals reflected from different directions by the spherical dish surface. A parabolic mirror would induce a varying [[w:astigmatism|astigmatism]] when the receiver is in different positions off the focal point, but the [[w:spherical aberration|error of a spherical mirror]] is the same in every direction."<ref name=AreciboObservatory>{{ cite web
|title=Arecibo Observatory, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 8,
|year=2012
|url=http://en.wikipedia.org/wiki/Arecibo_Observatory
|accessdate=2012-12-09 }}</ref>
At second lower left is the Evpatoria RT-70 radar telescope in the Ukraine.
At lower right is an artist's impression of the two radar satellites TerraSAR-X and TanDEM-X.
{{clear}}
=Radio interferometry=
[[Image:Interf diagram.gif|thumb|right|200px|The diagram shows a possible layout for an astronomical interferometer, with the mirrors laid out in a parabolic arrangement (similar to the shape of a conventional telescope mirror). Credit: .]]
“An '''astronomical interferometer''' is an [[w:array|array]] of telescopes or mirror segments acting together to probe structures with higher resolution by means of [[w:interferometry|interferometry]]. The benefit of the interferometer is that the [[w:angular resolution|angular resolution]] of the instrument is nearly that of a telescope with the same [[w:aperture|aperture]] as a single large instrument encompassing all of the individual photon-collecting sub-components. The drawback is that it does not collect as many photons as a large instrument of that size. Thus it is mainly useful for fine resolution of the more luminous astronomical objects, such as close [[w:binary star|binary star]]s.”<ref name=AstronomicalInterferometer>{{ cite web
|title=Astronomical interferometer, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 2,
|year=2012
|url=http://en.wikipedia.org/wiki/Astronomical_interferometer
|accessdate=2012-08-29 }}</ref>
“[[w:Very Long Baseline Interferometry|Very Long Baseline Interferometry]] uses a technique related to the [[w:closure phase|closure phase]] to combine telescopes separated by thousands of kilometers to form a radio interferometer with the resolution which would be given by a single dish which was thousands of kilometers in diameter. ... Astronomical interferometers can produce higher [[w:Angular resolution|resolution]] astronomical images than any other type of telescope. At radio wavelengths image resolutions of a few micro-[[w:arcsecond|arcsecond]]s have been obtained”<ref name=AstronomicalInterferometer/>.
{{clear}}
=Superluminal telescopes=
"The Cherenkov telescopes do not actually detect the gamma rays directly but instead detect the flashes of visible light [Cherenkov radiation] produced when gamma rays are absorbed by the Earth's atmosphere.<ref name=Penston>{{ cite web
|author = Margaret J. Penston
|date = 14 August 2002
|url=http://www.pparc.ac.uk/frontiers/latest/feature.asp?article=14F1&style=feature
|title = The electromagnetic spectrum
|publisher = Particle Physics and Astronomy Research Council
|accessdate = 17 August 2006 }}</ref>"<ref name=Astronomy>{{ cite web
|title=Astronomy, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 19,
|year=2012
|url=http://en.wikipedia.org/wiki/Astronomy
|accessdate=2012-07-28 }}</ref>
=Plasma-object telescopes=
[[Image:HallThruster 2.jpg|thumb|2 kW Hall thruster is in operation as part of the Hall Thruster Experiment at the Princeton Plasma Physics Laboratory. Credit: [[w:User:Dstaack|Dstaack]].]]
[[Image:Xenon hall thruster.jpg|thumb|This is a xenon 6 kW Hall thruster in operation at the NASA Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech.]]
"In [[w:spacecraft propulsion|spacecraft propulsion]], a '''Hall thruster''' is a type of [[w:ion thruster|ion thruster]] in which the [[w:propellant|propellant]] is accelerated by an [[w:electric field|electric field]]. Hall thrusters trap electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. Hall thrusters are sometimes referred to as '''Hall effect thrusters''' or '''Hall current thrusters'''. Hall thrusters are often regarded as a moderate [[w:specific impulse|specific impulse]] (1,600 s) [[w:space propulsion|space propulsion]] technology. ... Hall thrusters operate on a variety of propellants, the most common being xenon. Other propellants of interest include krypton, argon, bismuth, iodine, magnesium, and zinc."<ref name=HallEffectThruster>{{ cite web
|title=Hall effect thruster, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 16,
|year=2013
|url=http://en.wikipedia.org/wiki/Hall_effect_thruster
|accessdate=2013-05-28 }}</ref>
While these thrusters are not plasma-object telescopes, they may serve to maneuver or slew a space telescope. As sources of blue light they mat serve as calibrated light sources.
{{clear}}
=Gaseous-object telescopes=
[[Image:Sun Gun.jpg|thumb|right|200px|This is an image of a Sun Gun Telescope. Credit: .]]
The "'''Sun Gun Telescope''' [is] designed so that large groups of people can view the [[Sun (star)|sun]] safely - in particular it was created as a way to encourage children to become interested in [[astronomy]]. With this safe and portable device, both amateur science enthusiasts and professionals alike can observe sun spots."<ref name=SunGunTelescope>{{ cite web
|title=Sun Gun Telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 2,
|year=2013
|url=https://en.wikipedia.org/wiki/Sun_Gun_Telescope
|accessdate=2014-01-03 }}</ref>
The "Sun Gun [has] a 60mm dia. 900mm fl. optical tube which is mounted inside a 3" PVC which is in turn connected to a 20" plastic flower planter. A rear projection screen is ... mounted on the top of the flower planter. The entire Sun Gun can be made from items easily found at most local hardware stores. The scope itself is an inexpensive 60mm refractor available from many sources."<ref name=SunGunTelescope/>
{{clear}}
=Liquid-object telescopes=
[[Image:Liquid Mirror Telescope.jpg|thumb|right|This is a liquid mirror telescope. Credit: .]]
"'''Liquid mirror telescopes''' are telescopes with mirrors made with a reflective liquid. The most common liquid used is mercury, but other liquids will work as well (for example, low melting alloys of gallium). The container for the liquid is rotating so that the liquid assumes a paraboloidal shape. A paraboloidal shape is precisely the shape needed for the primary mirror of a telescope. The rotating liquid assumes the paraboloidal shape regardless of the container's shape. To reduce the amount of liquid metal needed, and thus weight, a rotating mercury mirror uses a container that is as close to the necessary parabolic shape as possible. Liquid mirrors can be a low cost alternative to conventional large telescopes. Compared to a solid glass mirror that must be cast, ground, and polished, a rotating liquid metal mirror is much less expensive to manufacture."<ref name=LiquidMirrorTelescope>{{ cite web
|title=Liquid mirror telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 1,
|year=2013
|url=https://en.wikipedia.org/wiki/Liquid_mirror_telescope
|accessdate=2014-01-03 }}</ref>
A "telescope with a liquid metal mirror can only be used [as a] zenith telescope that looks straight up".<ref name=LiquidMirrorTelescope/>
{{clear}}
=Rocky-object telescopes=
=Hydrogen telescopes=
[[Image:Solarborg.jpg|right|thumb|200px|Here is an example of an amateur solar telescope equipped with a hydrogen-alpha filter system. Credit: .]]
"In the field of [[amateur astronomy]] ... Amateurs use ... hydrogen-alpha filter systems".<ref name=SolarTelescope>{{ cite web
|title=Solar telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 30,
|year=2013
|url=https://en.wikipedia.org/wiki/Solar_telescope
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Ions=
=Compounds=
=Alloys=
[[Image:Cloudcroft Observatory.jpg|thumb|right|200px|The image shows the dome of the NASA Orbital Debris Observatory near Cloudcroft, New Mexico. Credit: NASA.]]
[[Image:CCD_Debris_Telescope.png|thumb|left|200px|This image shows the CCD Debris Telescope that is under the NODO dome. Credit: ]]
"The NASA-LMT was 3 m (9.8 ft) aperture liquid mirror telescope located in NODO's main dome. It consisted of a 3 m diameter parabolic dish that held 4 U.S. gallons (15 l) of a highly reflective liquid metal, mercury, spinning at a rate of 10 rpm, with sensors mounted above on a fixed structure. Due to the primary mirror's material, the NASA-LMT was configured as a zenith telescope. Using 20 narrowband filters, it cataloged space debris in Earth's orbit."<ref name=NASAOrbitalDebrisObservatory>{{ cite web
|title=NASA Orbital Debris Observatory, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 6,
|year=2013
|url=https://en.wikipedia.org/wiki/NASA_Orbital_Debris_Observatory
|accessdate=2014-01-03 }}</ref>
"The 32 cm (13 in) CCD Debris Telescope (CDT) was a portable Schmidt camera equipped with a 512×512 pixel charge-coupled device (CCD) sensor. It operated at NODO from October of 1997 until December of 2001, and was used to characterize debris at or near geosynchronous orbit."<ref name=NASAOrbitalDebrisObservatory/>
{{clear}}
=Atmospheres=
=Materials=
=Meteorites=
[[Image:Carancas Meteorite 2.jpg|thumb|right|200px|The image contains a 27.70 g fragment of the Carancas meteorite fall. The scale cube is 1 cm<sup>3</sup>. Credit: Meteorite Recon.]]
"On September 20, the X-Ray Laboratory at the Faculty of Geological Sciences, Mayor de San Andres University, [[w:La Paz, Bolivia|La Paz, Bolivia]], published a report of their analysis of a small sample of material recovered from the impact site. They detected iron, nickel, cobalt, and traces of iridium — elements characteristic of the elemental composition of meteorites. The quantitative proportions of silicon, aluminum, potassium, calcium, magnesium, and phosphorus are incompatible with rocks that are normally found at the surface of the Earth.<ref name=Blanco>Mario Blanco Cazas, [http://fcpn.umsa.bo/fcpn/app?service=external/PublicationDownload&sp=227 "Informe Laboratorio de Rayos X — FRX-DRX"] (in Spanish), Universidad Mayor de San Andres, Facultad de Ciencias Geologicas, Instituto de Investigaciones Geologicas y del Medio Ambiente, La Paz, Bolivia, September 20, 2007. Retrieved October 10, 2007.</ref>"<ref name=2007CarancasImpactEvent>{{ cite web
|title=2007 Carancas impact event, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 26,
|year=2013
|url=http://en.wikipedia.org/wiki/2007_Carancas_impact_event
|accessdate=2013-05-12 }}</ref>
{{clear}}
=Shelters=
"Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases, the entire upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes."<ref name=Observatory>{{ cite web
|title=Observatory, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=January 26,
|year=2013
|url=http://en.wikipedia.org/wiki/Observatory
|accessdate=2013-02-05 }}</ref>
=Spectroscopy=
"'''Astronomical spectroscopy''' is the technique of [[w:spectroscopy|spectroscopy]] used in [[astronomy]]. The object of study is the [[w:electromagnetic spectrum|spectrum]] of [[w:electromagnetic radiation|electromagnetic radiation]], including visible light, which [[w:radiant energy|radiates]] from [[w:star|star]]s and other celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition, but also their motion by [[w:Doppler shift|Doppler shift]] measurements."<ref name=AstronomicalSpectroscopy>{{ cite web
|title=Astronomical spectroscopy, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 8,
|year=2012
|url=http://en.wikipedia.org/wiki/Astronomical_spectroscopy
|accessdate=2013-01-09 }}</ref>
=Spectrometers=
[[Image:Osse.gif|thumb|right|200px|The Oriented Scintillation Spectrometer Experiment (OSSE) consists of four NaI scintillation detectors, sensitive to energies from 50 keV to 10 MeV. Credit: NASA GSFC.]]
"The Oriented Scintillation Spectrometer Experiment (OSSE) will conduct a broad range of observations in the 0.05-250 MeV energy range. Major emphasis is placed on scientific objectives in the 0.1-10.0 MeV region with a limited capability above 10 MeV, primarily for observations of solar gamma-rays and neutrons and observations of high-energy emission from pulsars."<ref name=Johnson>{{ cite web
|author=W. N. Johnson
|title=Appendix G to the NASA RESEARCH ANNOUNCEMENT for the COMPTON GAMMA RAY OBSERVATORY GUEST INVESTIGATOR PROGRAM
|publisher=National Aeronautics and Space Administration Goddard Space Flight Center
|location=Greenbelt, Maryland USA
|month=November
|year=1996
|url=http://heasarc.gsfc.nasa.gov/docs/cgro/nra/appendix_g.html#III.%20COMPTEL%20GUEST%20INVESTIGATOR%20PROGRAM
|accessdate=2013-04-05 }}</ref>
{{clear}}
=Planetary telescopes=
[[Image:Goto telescope.jpg|thumb|right|A telescope on an alt-azimuth GoTo mount. Note the keypad, resting on the platform between the tripod's legs, that is the telescope's hand control. Batteries are stored in the circular compartment just above the tripod. In this picture, the compartment is just above the hand control.]]
"In [[amateur astronomy]], "'''GoTo'''" refers to a type of [[telescope mount]] and related [[software]] which can automatically point a telescope to [[astronomical objects]] that the user selects. Both axes of a GoTo mount are motor driven and are controlled by either a microprocessor-based integrated controller or a personal computer, as opposed to the single axis semi-automated tracking of a traditional clock drive mount. This allows the user to command the mount to point the telescope to a right ascension and declination that the user inputs or have the mount itself point the telescope to objects in a pre-programmed data base including ones from the Messier catalogue, the New General Catalogue, and even major solar system bodies (the Sun, Moon, and planets)."<ref name=GoToTelescopes>{{ cite web
|title=GoTo (telescopes), In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 27.
|year=2013
|url=https://en.wikipedia.org/wiki/GoTo_(telescopes)
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Solar telescopes=
[[Image:Kitt Peak McMath-Pierce Solar Telescope.jpg|thumb|right|200px|This view is of the McMath-Pierce Solar Telescope at Kitt Peak National Observatory, near Tucson, Arizona. Credit: [http://www.flickr.com/photos/oceanyamaha/ ocean yamaha].]]
"A '''solar telescope''' is a special purpose [[w:telescope|telescope]] used to observe the [[Sun (star)|Sun]]. Solar telescopes usually detect light with wavelengths in, or not far outside, the [[w:visible spectrum|visible spectrum]]."<ref name=SolarTelescope>{{ cite journal
|title=Solar telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 31,
|year=2012
|url=http://en.wikipedia.org/wiki/Solar_telescope
|pdf=
|accessdate=2012-07-07 }}</ref>
{{clear}}
=Asteroid telescopes=
[[Image:Lowell astrograph.jpg|thumb|200px|right|The Lowell astrograph is a dedicated astrophotography telescope. Credit: .]]
The Lowell astrograph imaged at right is a 13-inch, f/5.3 astrograph at Lowell Observatory, a refractor with a 3 element Cooke triplet lens.<ref name=Tombaugh>{{ cite web
|author=Clyde W. Tombaugh
|title=The Struggles to Find the Ninth Planet
|url=http://ircamera.as.arizona.edu/NatSci102/NatSci102/text/ext9thplanet.htm }}</ref>) that was used in the discovery of [[Pluto]].
"An '''astrograph''' ('''astrographic camera''') is a telescope designed for the sole purpose of astrophotography. Astrographs are usually used in wide field surveys of the night sky as well as detection of objects such as [[asteroids]], [[meteor]]s, and [[comet]]s."<ref name=Astrograph>{{ cite web
|title=Astrograph, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 12,
|year=2013
|url=https://en.wikipedia.org/wiki/Astrograph
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Comet seeker telescopes=
"A comet seeker is a type of small telescope adapted especially to searching for comets: commonly of short focal length and large aperture, in order to secure the greatest brilliancy of light."<ref name=CometSeeker>{{ cite web
|title=Comet seeker, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 6,
|year=2013
|url=https://en.wikipedia.org/wiki/Comet_seeker
|accessdate=2014-01-03 }}</ref>
=Stellar telescopes=
[[File:FASTT Transit Circle.jpg|thumb|right|200px|The Ron Stone/Flagstaff Astrometric Scanning Transit Telescope of the U.S.Naval Observatory, built by Farrand Optical Company, 1981, is imaged. Credit: .]]
"The '''meridian circle''' is an instrument for timing of the passage of [[stars]] across the local meridian, an event known as a transit, while at the same time measuring their angular distance from the nadir. These are special purpose telescopes mounted so as to allow pointing only in the meridian, the great circle through the north point of the horizon, the zenith, the south point of the horizon, and the nadir. Meridian telescopes rely on the rotation of the Earth to bring objects into their field of view and are mounted on a fixed, horizontal, east-west axis."<ref name=MeridianCircle>{{ cite web
|title=Meridian circle, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 6,
|year=2013
|url=https://en.wikipedia.org/wiki/Meridian_circle
|accessdate=2014-01-03 }}</ref>
"A modern day example of this type of telescope is the 8 inch (~0.2m) Flagstaff Astrometric Scanning Transit Telescope (FASTT) at the [United States Naval Observatory] USNO Flagstaff Station Observatory.<ref name=NOFS>{{cite web
|url=http://www.nofs.navy.mil/about_NOFS/telescopes/fastt.html
|title=About NOFS telescopes }}</ref> Modern meridian circles are usually automated. The observer is replaced with a [Charge-coupled device] CCD camera. As the sky drifts across the field of view, the image built up in the CCD is clocked across (and out of) the chip at the same rate. This allows some improvements:<ref name=Stone>{{ cite web
|url=http://articles.adsabs.harvard.edu//full/1990IAUS..141..369S/0000369.000.html
|title=The USNO (Flagstaff Station) CCD Transit Telescope and Star Positions Measured From Extragalactic Sources
|first1=Ronald C.
|last1=Stone
|first2=David G.
|last2=Monet
|year=1990
|journal=Proceedings of IAU Symposium No. 141
|pages=369–370 }}</ref>"<ref name=MeridianCircle/>
{{clear}}
=Galactic telescopes=
[[Image:NGC 891 HST.jpg|thumb|right|200px|NGC 891 is selected as first light. Credit: NASA.]]
[[Image:LargeBinoTelescope NASA.jpg|thumb|left|200px|This is an image of the Large Binocular Telescope with protective doors open. Credit: NASA.]]
The Large Binocular Telescope [at left] is "located on Mount Graham (10,700-foot (3,300 m)) in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory."<ref name=LargeBinocularTelescope>{{ cite web
|title=Large Binocular Telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 21,
|year=2013
|url=http://en.wikipedia.org/wiki/Large_Binocular_Telescope
|accessdate=2013-07-02 }}</ref>
"The first image taken [shown at right] combined ultraviolet and green light, and emphasizes the clumpy regions of newly formed hot stars in the spiral arms."<ref name=LargeBinocularTelescope/>
{{clear}}
=Chemistry=
=Geography=
[[Image:VERITAS array.jpg|thumb|right|300px|VERITAS is located at the basecamp of the Smithsonian Astrophysics Observatory's Fred Lawrence Whipple Observatory (FLWO) in southern Arizona. Credit: VERITAS.]]
[[Image:Aerial View of the VLTI with Tunnels Superimposed.jpg|200px|thumb|left|The four Unit Telescopes form the VLT together with the Auxiliary Telescopes. Credit: .]]
"VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based gamma-ray instrument operating at the Fred Lawrence Whipple Observatory (FLWO) in southern Arizona, USA. It is an array of four 12m optical reflectors for gamma-ray astronomy in the GeV - TeV energy range. These imaging Cherenkov [a bluish light] telescopes are deployed such that they have the highest sensitivity in the VHE energy band (50 GeV - 50 TeV), with maximum sensitivity from 100 GeV to 10 TeV. This VHE observatory effectively complements the NASA Fermi mission."<ref name=Fortin>{{ cite web
|author=Pascal Fortin
|title=VERITAS Very Energetic Radiation Imaging Telescope Array System
|publisher=Smithsonian Astrophysical Observatory
|location=Amado, Arizona USA
|month=April 14
|year=2013
|url=http://veritas.sao.arizona.edu/
|pdf=
|accessdate=2013-06-01 }}</ref>
The Collaboration between Australia and Nippon for a Gamma Ray Observatory in the Outback, (CANGAROO) is for "[v]ery high energy cosmic gamma ray observation by telescope [detecting Cherenkov light]. [It is] [l]ocated on the [[w:Woomera Prohibited Area|Woomera Prohibited Area]] in South Australia. <ref name=CANGAROO>{{ cite web
|url=http://www.physics.adelaide.edu.au/astrophysics/cangaroo/index.html
|title=The CANGAROO Project
|publisher=The University of Adelaide
|accessdate=17 September 2011 }}</ref>"<ref name=InstituteforCosmicRayResearch>{{ cite web
|title=Institute for Cosmic Ray Research, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 28,
|year=2013
|url=http://en.wikipedia.org/wiki/Institute_for_Cosmic_Ray_Research
|accessdate=2013-06-01 }}</ref>
"The Very Large Telescope (VLT) is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. ... The UTs are equipped with a large set of instruments permitting observations to be performed [in] the near-ultraviolet" ... It includes large-field imagers, adaptive optics corrected cameras and spectrographs, as well as high-resolution and multi-object spectrographs and covers a broad spectral region, from [the] deep ultraviolet (300 nm)".<ref name=VeryLargeTelescope>{{ cite web
|title=Very Large Telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 17,
|year=2013
|url=http://en.wikipedia.org/wiki/Very_Large_Telescope
|accessdate=2013-07-02 }}</ref>
{{clear}}
=History=
[[File:TransitCircle USNO.jpg|thumb|right|200px|This is the 6-inch transit circle of the U.S. Naval Observatory. Credit: .]]
The 6-inch transit circle [imaged at right] of the U.S. Naval Observatory was built by Warner and Swasey in 1898.
{{clear}}
=Mathematics=
=Physics=
=Science=
=Technology=
=Apertures=
"Some X-ray telescopes use coded aperture imaging. This technique uses a flat aperture grille in front of the detector, which weighs much less than any kind of focusing X-ray lens, but requires considerably more post-processing to produce an image."<ref name=XRayTelescope>{{ cite web
|title=X-ray telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 17,
|year=2012
|url=http://en.wikipedia.org/wiki/X-ray_telescope
|accessdate=2012-06-15 }}</ref>
=Mirrors=
[[Image:Wolter-types.gif|thumb|right|200px|This is a diagram of Wolter telescopes of Types I, II, and III. Credit: .]]
"The mirrors can be made of ceramic or metal foil.<ref name=xraysMirror>{{ cite web |title=Mirror Laboratory |url=http://astrophysics.gsfc.nasa.gov/xrays/MirrorLab/xoptics.html }}</ref> The most commonly used grazing angle incidence materials for X-ray mirrors are [[w:gold|gold]] and [[w:iridium|iridium]]. The critical reflection angle is energy dependent. For gold at 1 keV, the critical reflection angle is 3.72 degrees. A limit for this technology in the early 2000s with Chandra and XMM-Newton was about 15 keV light.<ref name=nustar1>[http://www.nustar.caltech.edu/about-nustar/instrumentation/optics NuStar: Instrumentation: Optics]</ref> Using new multi-layered coatings, computer aided manufacturing, and other techniques the [X-ray] mirror for the [[w:Nuclear Spectroscopic Telescope Array|NuStar]] telescope pushed this up to 79 keV light.<ref name=nustar1/> To reflect at this level, glass layers were multi-coated with Tungsten (W)/Silicon (Si) or Platinum(Pt)/Siliconcarbite(SiC).<ref name=nustar1/>."<ref name=XRayTelescope/>
"Although optical telescopes can image the near ultraviolet, the [[w:ozone layer|ozone layer]] in the [[w:stratosphere|stratosphere]] absorbs ultraviolet radiation shorter than 300 nm so most ultra-violet astronomy is conducted with satellites. Ultraviolet telescopes [10 nm - 400 nm] resemble optical telescopes, but conventional [[w:aluminium|aluminium]]-coated mirrors cannot be used and alternative coatings such as [[w:magnesium fluoride|magnesium fluoride]] or [[w:lithium fluoride|lithium fluoride]] are used instead. The [[w:Orbiting Solar Observatory|OSO 1]] satellite carried out observations in the ultra-violet as early as 1962. The [[w:International Ultraviolet Explorer|International Ultraviolet Explorer]] (1978) systematically surveyed the sky for eighteen years, using a 45 cm (18 in) aperture telescope with two [[w:spectroscope|spectroscope]]s. Extreme-ultraviolet astronomy (10–100 nm) is a discipline in its own right and involves many of the techniques of X-ray astronomy; the [[w:Extreme Ultraviolet Explorer|Extreme Ultraviolet Explorer]] (1992) was a satellite operating at these wavelengths."<ref name=Historyofthetelescope>{{ cite web
|title=History of the telescope, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 10,
|year=2012
|url=http://en.wikipedia.org/wiki/History_of_the_telescope
|accessdate=2012-06-26 }}</ref>
{{clear}}
=Modulation collimators=
[[Image:Four-wire grid modulation collimator.jpeg|thumb|right|200px|The diagram shows the principles of operation of the four-grid modulation collimator. Credit: H. Bradt, G. Garmire, M. Oda, G. Spada, and B.V. Sreekantan, P. Gorenstein and H. Gursky.]]
A modulation collimator consists of “two or more wire grids [diffraction gratings] placed in front of an X-ray sensitive Geiger tube or proportional counter.”<ref name=Bradt>{{ cite journal
|author=H. Bradt, G. Garmire, M. Oda, G. Spada, and B.V. Sreekantan, P. Gorenstein and H. Gursky
|title=The Modulation Collimator in X-ray Astronomy
|journal=Space Science Reviews
|month=September
|year=1968
|volume=8
|issue=4
|pages=471-506
|url=
|arxiv=
|bibcode=1968SSRv....8..471B
|doi=10.1007/BF00175003
|pmid=
|pdf=
|accessdate=2011-12-10 }}</ref> Relative to the path of incident X-rays (incoming X-rays) the wire grids are placed one beneath the other with a slight offset that produces a shadow of the upper grid over part of the lower grid.<ref name=Oda>{{ cite journal
|author=Minoru Oda
|title=High-Resolution X-Ray Collimator with Broad Field of View for Astronomical Use
|journal=Applied Optics
|month=January
|year=1965
|volume=4
|issue=1
|pages=143
|url=http://www.opticsinfobase.org/abstract.cfm?URI=ao-4-1-143
|arxiv=
|bibcode=1965ApOpt...4..143O
|doi=10.1364/AO.4.000143
|pmid=
|pdf=http://www.opticsinfobase.org/ao/viewmedia.cfm?uri=ao-4-1-143&seq=0
|accessdate=2011-12-10 }}</ref>
{{clear}}
=Computers=
[[Image:Lights glowing on the ALMA correlator.jpg|thumb|right|200px|The ALMA correlator is one of the most powerful supercomputers in the world. Credit: ALMA (ESO/NAOJ/NRAO), S. Argandoña.]]
"The ALMA correlator [shown at right], one of the most powerful supercomputers in the world, has now been fully installed and tested at its remote, high altitude site in the Andes of northern Chile. This view shows lights glowing on some of the racks of the correlator in the ALMA Array Operations Site Techical Building. This photograph shows one of the four quadrants of the correlator. The full system has four identical quadrants, with over 134 million processors, performing up to 17 quadrillion operations per second."<ref name=ALMAObservatory>{{ cite web
|author=ALMA Observatory
|title=Lights glowing on the ALMA correlator
|publisher=ALMA Observatory Organization
|location=Atacama, chile
|month=July 10,
|year=2013
|url=http://www.almaobservatory.org/en/visuals/images/the-alma-observatory/?g2_itemId=3939
|pdf=
|accessdate=2013-07-21 }}</ref>
{{clear}}
=Mounts=
“A telescope mount is a mechanical structure which supports a telescope. Telescope mounts are designed to support the mass of the telescope and allow for accurate pointing of the instrument.”<ref name=Telescope>{{ cite journal
|title=Telescope
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 4,
|year=2012
|url=http://en.wikipedia.org/wiki/Telescope
|pdf=
|accessdate=2012-07-07 }}</ref>
'''Def.''' “an object on which another object”<ref name=Mount>{{ cite journal
|title=mount
|journal=Wiktionary
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 8,
|year=2012
|url=http://en.wiktionary.org/wiki/mount
|pdf=
|accessdate=2012-07-07 }}</ref> is attached for support is called a '''mount'''.
=Altazimuth mounts=
[[Image:heliostat.jpg|right|200px|thumb|A [[w:heliostat|heliostat]] is shown at the THÉMIS experimental station in France. The mirror rotates on an alt-azimuth mount. The pointing direction of the mirror is perpendicular to its surface. Credit: .]]
“An '''altazimuth''' or '''alt-azimuth mount''' is a simple two-[[w:coordinate axis|axis]] mount for supporting and rotating an instrument about two mutually [[w:perpendicular|perpendicular]] axes; one vertical and the other horizontal. Rotation about the vertical axis varies the [[w:azimuth|azimuth]] (compass bearing) of the pointing direction of the instrument. Rotation about the horizontal axis varies the [[w:altitude|altitude]] (angle of elevation) of the pointing direction.” from the Wikipedia article about the [[w:Altazimuth mount|altazimuth mount]].
“When used as an astronomical [[w:telescope mount|telescope mount]], the biggest advantage of an alt-azimuth mount is the simplicity of its mechanical design. The primary disadvantage is its inability to follow astronomical objects in the [[w:night sky|night sky]] as the [[Earth]] spins on its axis the way that an [[w:equatorial mount|equatorial mount]] can. Equatorial mounts only need to be rotated about a single axis, at a constant rate, to follow the rotation of the night sky ([[w:diurnal motion|diurnal motion]]). Altazimuth mounts need to be rotated about both axes at variable rates, achieved via [[w:microprocessor|microprocessor]] based two-axis drive systems, to track equatorial motion. This imparts an uneven rotation to the field of view that also has to be corrected via a microprocessor based counter rotation system.<ref name=Mahra>{{ cite journal
| author = H. S. Mahra, B. N. Karkera
| title = Field rotation with altazimuth mounting telescope
| journal = Bulletin of the Astronomical Society of India
| volume = 13
| issue =
| pages = 88
| publisher =
| year = 1985 }}</ref> On smaller telescopes an [[w:equatorial platform|equatorial platform]]<ref>{{cite web
| author = Reiner Vogel
| title = Circle Segment Platform (link from his English language page)
| date =
| year = 2007
| url = http://www.reinervogel.net/index_e.html
| accessdate = 13 March 2011 }}</ref> is sometimes used to add a third "polar axis" to overcome these problems, providing an hour or more of motion in the direction of [[w:right ascension|right ascension]] to allow for astronomical tracking. The design also does not allow for the use of mechanical [[w:setting circles|setting circles]] to locate astronomical objects although modern [[w:Setting circles#Digital setting circles|digital setting circles]] have removed this shortcoming.” per the Wikipedia article about the [[w:Altazimuth mount|altazimuth mount]].
{{clear}}
=Equatorial mounts=
“The equatorial mount has north-south "polar axis" tilted to be parallel to Earth's polar axis that allows the telescope to swing in an east-west arc, with a second axis perpendicular to that to allow the telescope to swing in a north-south arc. Slewing or mechanically driving the mounts polar axis in a counter direction to the Earth's rotation allows the telescope to accurately follow the motion of the night sky.” from the Wikipedia articl about the [[w:Telescope mount|telescope mount]].
=Hexapod mounts=
[[Image:DOT main mirror.jpg|thumb|right|200px|This is an image of the top part of the Dutch Open Telescope. Credit: Tim van Werkhoven.]]
“Instead of the classical mounting using two axles, the mirror is supported by six extendable struts (hexapod). This configuration allows moving the telescope in all six spatial degrees of freedom and also provides a strong structural integrity.” per the Wikipedia article on the [[w:Telescope mount|telescope mount]].
{{clear}}
=Clock drives=
[[Image:Aldershot observatory 02.JPG|thumb|right|200px|The clock drive mechanism in the pier of the german equatorial mount for the 8-inch refracting telescope at [[w:Aldershot Observatory|Aldershot Observatory]] is shown in the image. Credit: .]]
"[A] '''Clock drive''' is a regulatory mechanism used to move an [[w:equatorial mount|equatorial mount]]ed [[telescope]] along one [[w:Axis of rotation|axis]] to keep the telescope in exact sync with the apparent motion of the celestial sky ([[w:diurnal motion|diurnal motion]]).<ref name=ClockDriveDefinition>{{ cite web
|url=http://www.answers.com/topic/clock-drive
|title=Definition }}</ref>"
"Clock drives work by rotating a [[w:telescope mount|telescope mount]]'s polar axis, the axis parallel to the Earth's polar axis (also called the [[w:Right ascension|right ascension]] axis) in the opposite direction to the Earth's rotation one revolution every 23 hours and 56 minutes (called ''[[w:Sidereal time|sidereal day]]''), thereby canceling that motion.<ref name=Consolmagno>{{ cite book
|url=http://books.google.com/books?id=PexKTfPy3voC&pg=PA204&dq=%22called+a+clock+drive%22&hl=en&ei=etnITMabMIH_8Aa8v8StDw&sa=X&oi=book_result&ct=result&resnum=10&ved=0CFEQ6AEwCQ#v=onepage&q=%22called%20a%20clock%20drive%22&f=false
|title=Turn left at Orion: a hundred night sky objects to see in a small telescope ...
|author=Guy Consolmagno, Dan M. Davis, Karen Kotash Sepp, Anne Drogin, Mary Lynn Skirvin
|pages=204 }}</ref> This allows the telescope to stay [fixed] on a certain point in the sky without having to be constantly re-aimed due to the Earth's rotation. The mechanism itself used to be [[w:clockwork|clockwork]] but nowadays is usually electrically driven. Clock drives can be light and portable for smaller telescopes<ref name=Oltion>{{ cite web
| author = Jerry Oltion|
| title = The Trackball Mount
| url = http://www.sff.net/people/j.oltion/trackball_mount.htm
| accessdate = 13 March 2011 }}</ref> or can be exceedingly heavy and complex for larger ones such as the 60 inch telescope at the [[w:Mount Wilson Observatory|Mount Wilson Observatory]].<ref name=SixtyInchClock>{{ cite web
|url=http://www.oldengine.org/members/levans/60clock/
|title=60 inch clock (the old Mount Wilson telescope clock drive) }}</ref> Clock-driven [[w:equatorial platform|equatorial platform]]s are sometimes used in non-tracking type mounts, such as [[w:altazimuth mount|altazimuth mount]]s.<ref name=Vogel>{{ cite web
| author = Reiner Vogel
| title = Circle Segment Platform (link from his English language page)
| year = 2007
| url = http://www.reinervogel.net/index_e.html
| accessdate = 13 March 2011 }}</ref>"<ref name=ClockDrive>{{ cite journal
|title=Clock drive
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 30,
|year=2012
|url=http://en.wikipedia.org/wiki/Clock_drive
|pdf=
|accessdate=2012-07-07 }}</ref>
{{clear}}
=Clocks=
[[Image:FOCS-1.jpg|thumb|left|200px| The FOCS 1 is a continuous cold caesium fountain atomic clock in Switzerland. Credit: .]]
"An '''atomic clock''' is a [[w:clock|clock]] device that uses an [[w:electronic transition|electronic transition]] [[w:frequency|frequency]] in the [[w:microwave|microwave]], [[w:light|optical]], or [[w:ultraviolet|ultraviolet]] region<ref name=McCarthy>{{ cite book
|title=TIME from Earth Rotation to Atomic Physics
|author=Dennis McCarthy, P. Kenneth Seidelmann
|at=ch. 10 & 11
|location=Weinheim
|publisher=Wiley-VCH
|year=2009 }}</ref> of the [[w:electromagnetic spectrum|electromagnetic spectrum]] of [[w:atoms|atoms]] as a [[w:frequency standard|frequency standard]] for its timekeeping element. Atomic clocks are the most accurate [[w:time standard|time]] and [[w:frequency standard|frequency standard]]s known, and are used as [[w:primary standard|primary standard]]s for international [[w:Time dissemination|time distribution services]], to control the wave frequency of television broadcasts, and in [[w:global navigation satellite system|global navigation satellite system]]s such as [[w:GPS|GPS]]."<ref name=AtomicClock>{{ cite web
|title=Atomic clock, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 12,
|year=2012
|url=http://en.wikipedia.org/wiki/Atomic_clock
|accessdate=2012-10-24 }}</ref>
The FOCS 1 continuous cold cesium fountain atomic clock started operating in 2004 at an uncertainty of one second in 30 million years. The clock is in Switzerland.
{{clear}}
=Motion calibrators=
"'''POA CALFOS''' is the improved Post Operational Archive version of the [[w:Faint Object Spectrograph|Faint Object Spectrograph]] (FOS) calibration pipeline ... The current version corrects for image motion problems that have led to significant wavelength scale uncertainties in the FOS data archive. The improvements in the calibration enhance the scientific value of the data in the FOS archive, making it a more homogeneous and reliable resource."<ref name=POACALFOS>{{ cite web
|title=POA CALFOS, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 22
|year=2012
|url=http://en.wikipedia.org/wiki/POA_CALFOS
|accessdate=2012-12-23 }}</ref>
=Detectors=
[[Image:Proportional Counter Array RXTE.jpg|thumb|right|200px|This is an image of a real X-ray detector. The instrument is called the Proportional Counter Array and it is on the [[w:Rossi X-ray Timing Explorer|Rossi X-ray Timing Explorer]] (RXTE) satellite. Credit: .]]
"[[Radiation detectors]] provide a signal that is converted to an electric current. The device is designed so that the current provided is proportional to the characteristics of the incident radiation."<ref name=RadiationDetectors>{{ cite web
|title=Radiation detectors, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 19,
|year=2012
|url=http://en.wikiversity.org/wiki/Radiation_detectors
|accessdate=2012-07-07 }}</ref>
Detectors such as the X-ray detector at right collect individual X-rays (photons of X-ray light), count them, discern the energy or wavelength, or how fast they are detected. The detector and telescope system can be designed to yield temporal, spatial, or spectral information.
{{clear}}
=Image processors=
'''Def.''' “[a]ny form of information processing for which both the input and output are images”, after Wiktionary [[wikt:image processing|image processing]], is called '''image processing'''.
'''Def.''' “[a] representation of anything ... upon canvas, paper, or other surface”, after Wiktionary [[wikt:picture|picture]], is called a '''picture'''.
'''Def.''' a “representation of a real object”, after Wiktionary [[wikt:image|image]] is called an image.
'''Def.''' “[t]he set of points that map to a given point (or set of points) under a specified function”, from Wiktionary [[wikt:inverse image|inverse image]], is called an inverse image.
“Under the function given by <math>f(x)=x^2</math>, the '''inverse image''' of 4 is <math>\{-2,2\}</math>, as is the '''inverse image''' of <math>\{4\}</math>”, after Wiktionary [[wikt:inverse image|inverse image]].
A telescope's "imaging system's resolution can be limited either by [[w:Optical aberration|aberration]] or by [[w:diffraction|diffraction]] causing [[w:Focus (optics)|blurring]] of the image. These two phenomena have different origins and are unrelated. Aberrations can be explained by geometrical optics and can in principle be solved by increasing the optical quality — and cost — of the system. On the other hand, diffraction comes from the wave nature of light and is determined by the finite aperture of the optical elements. The [[w:lens (optics)|lens]]' circular [[w:aperture|aperture]] is analogous to a two-dimensional version of the [[w:Slit experiment|single-slit experiment]]. Light passing through the lens [[w:Interference (wave propagation)|interferes]] with itself creating a ring-shape diffraction pattern, known as the [[w:Airy pattern|Airy pattern]], if the [[w:wavefront|wavefront]] of the transmitted light is taken to be spherical or plane over the exit aperture."<ref name=AngularResolution>{{ cite web
|title=Angular resolution, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 20,
|year=2012
|url=http://en.wikipedia.org/wiki/Angular_resolution
|accessdate=2013-01-10 }}</ref>
"The interplay between diffraction and aberration can be characterised by the [[w:point spread function|point spread function]] (PSF). The narrower the aperture of a lens the more likely the PSF is dominated by diffraction."<ref name=AngularResolution/>
"Two point sources are regarded as just resolved when the principal diffraction maximum of one image coincides with the first minimum of the other.<ref name=Born>{{ cite book
| author = Max Born and Emil Wolf
| title = Principles of Optics
| publisher = Cambridge University Press
| date = October 1999
| location = Cambridge
| page = 461
| isbn = 0-521-64222-1}}</ref>"<ref name=AngularResolution/>
=Robotic telescopes=
[[Image:El Enano robotic telescope.jpg|thumb|right|200px|“El Enano” is a robotic telescope. Credit: .]]
"A '''robotic telescope''' is an astronomical telescope and detector system that makes observations without the intervention of a human. In astronomical disciplines, a telescope qualifies as robotic if it makes those observations without being operated by a human, even if a human has to initiate the observations at the beginning of the night, or end them in the morning. A robotic telescope is distinct from a remote telescope, though an instrument can be both robotic and remote."<ref name=RoboticTelescope>{{ cite web
|title=article title, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 1,
|year=2013
|url=https://en.wikipedia.org/wiki/Robotic_telescope
|accessdate=2014-01-03 }}</ref>
{{clear}}
=Spotting telescopes=
[[Image:Yukon spotting scope.jpg|thumb|right|200px|This is a 100 mm spotting scope with a coaxial 30 mm finderscope. Credit: .]]
"A '''spotting scope''' is a small portable [[telescope]] with added optics to present an [[erect image]], optimized for the observation of terrestrial objects."<ref name=SpottingScope>{{ cite web
|title=article title, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 28,
|year=2013
|url=https://en.wikipedia.org/wiki/Spotting_scope
|accessdate=2014-01-03 }}</ref>
"The light-gathering power and [angular] resolution of a spotting scope is determined by the diameter of the objective lens, typically between 50 and 80 mm. The larger the objective, the more massive and expensive the telescope."<ref name=SpottingScope/>
"The optical assembly has a small refracting objective lens, an image erecting system that uses either image erecting relay lenses or prisms (porro prisms or roof prisms), and an eyepiece that is usually removable and interchangeable to give different magnifications. Other telescope designs are used such as Schmidt and Maksutov optical assemblies. They may have a ruggedised design, a mounting for attaching to a tripod, and an ergonomically designed and located knob for focus control."<ref name=SpottingScope/>
{{clear}}
=Observatories=
[[Image:Champaign-Urbana area IMG 1138.jpg|right|thumb|200px|This equatorial room is at the University of Illinois Observatory. Credit: .]]
"Historically, observatories [are] as simple as [using or placing stably] an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena). ... Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases, the entire upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes."<ref name=Observatory>{{ cite journal
|title=Observatory
|journal=Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 11,
|year=2012
|url=http://en.wikipedia.org/wiki/Astronomical_observatory
|pdf=
|accessdate=2012-05-15 }}</ref>
“An '''equatorial room''', in [[w:Observatory#Astronomical_observatories|astronomical observatories]], is the room which contains an [[w:equatorial mount|equatorial mount]]ed [[w:telescope|telescope]]. It is usually referred to in observatory buildings that contain more than one type of instrument: for example buildings with an "equatorial room" containing an equatorial telescope and a "transit room" containing a [[w:transit telescope|transit telescope]].<ref name=Chabot>{{ cite journal
|url=http://adsabs.harvard.edu/full/1894PASP....6...85B
|title=The CHABOT Observatory
|journal=Publications of the Astronomical Society of the Pacific
|volume=6
|issue=35
|page=85 }}</ref> Equatorial rooms tend to be large circular rooms to accommodate all the range of motion of a long telescope on an equatorial mount and are usually topped with a dome to keep out the weather.”<ref name=EquatorialRoom>{{ cite web
|title=Equatorial room, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 14,
|year=2012
|url=http://en.wikipedia.org/wiki/Equatorial_room
|accessdate=2012-07-07 }}</ref>
{{clear}}
=Lofting technology=
Many devices for lofting technology have been developed to improve [[radiation astronomy]].
=Balloons=
[[Image:BLAST on flightline kiruna 2005.jpeg|thumb|right|200px|BLAST is hanging from the launch vehicle in [[w:Esrange|Esrange]] near [[w:Kiruna|Kiruna]], [[w:Sweden|Sweden]] before launch June 2005. Credit: [[commons:User:Mtruch|Mtruch]].]]
[[Image:NASA Launches Telescope-Toting Balloon from-c3425de80831dab2a243aae9e0372fe7.jpeg|thumb|left|200px|NASA's balloon-carried BLAST sub-millimeter telescope is hoisted into launch position on Dec. 25, 2012, at McMurdo Station in Antarctica. Credit: NASA/Wallops Flight Facility.]]
“The '''Balloon-borne Large Aperture Submillimeter Telescope''' ('''BLAST''') is a submillimeter [[w:telescope|telescope]] that hangs from a [[w:high altitude balloon|high altitude balloon]]. It has a 2 meter primary mirror that directs light into [[w:bolometer|bolometer]] arrays operating at 250, 350, and 500 µm. ... BLAST's primary science goals are:<ref>[http://blastexperiment.info/ BLAST Public Webpage]</ref>
*Measure photometric [[w:redshift|redshift]]s, rest-frame [[w:Far infrared|FIR]] luminosities and star formation rates of high-redshift [[w:starburst galaxies|starburst galaxies]], thereby constraining the evolutionary history of those galaxies that produce the FIR/submillimeter background.
*Measure cold pre-stellar sources associated with the earliest stages of [[w:star formation|star]] and [[w:planet formation|planet formation]].
*Make high-resolution maps of [[interstellar medium|diffuse galactic emission]] over a wide range of galactic latitudes.”<ref name=BLASTtelescope>{{ cite web
|title=BLAST (telescope), In: 'Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 4,
|year=2012
|url=http://en.wikipedia.org/wiki/BLAST_(telescope)
|accessdate=2012-06-08 }}</ref>
“[[w:high-altitude balloon|High-altitude balloon]]s and aircraft ... can get above [much] of the atmosphere. The [[w:BLAST (telescope)|BLAST]] experiment and [[w:SOFIA|SOFIA]] are two examples, respectively, although SOFIA can also handle near infrared observations.”<ref name=Submillimetreastronomy>{{ cite web
|title=Submillimetre astronomy, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 2,
|year=2012
|url=http://en.wikipedia.org/wiki/Submillimetre_astronomy
|accessdate=2012-06-08 }}</ref>
At left above "NASA's balloon-carried BLAST sub-millimeter telescope is hoisted into launch position on Dec. 25, 2012, at McMurdo Station in Antarctica on a mission to peer into the cosmos."<ref name=SpaceDotCom>{{ cite web
|author=SPACE.com
|title=NASA Launches Telescope-Toting Balloon from Antarctica on Christmas
|publisher=SPACE.com
|location=
|month=December 25,
|year=2012
|url=http://news.yahoo.com/photos/nasa-launches-telescope-toting-balloon-antarctica-christmas-photo-164200244.html;_ylt=AoHsK.HbhPGTU8L1bT1.REEbANEA;_ylu=X3oDMTRramh0MW1uBG1pdANBcnRpY2xlIFJlbGF0ZWQgQ2Fyb3VzZWwEcGtnA2IyNDU3MjZmLTQ0NjQtMzJjMC05NGY2LTM5MGUxYTdkMjhkMgRwb3MDMQRzZWMDTWVkaWFBcnRpY2xlUmVsYXRlZENhcm91c2VsBHZlcgMwNzE3Yjc3MC00ZjdjLTExZTItYWQ1ZC05ODBjY2Q0Njg5OGQ-;_ylg=X3oDMTNhNjM2ZDhuBGludGwDdXMEbGFuZwNlbi11cwRwc3RhaWQDOWMzMDIyNDctMWM5NS0zMGYwLWIzNGItNDZjMjJkMjY0MmUyBHBzdGNhdANzY2llbmNlfHNwYWNlLWFzdHJvbm9teQRwdANzdG9yeXBhZ2U-;_ylv=3
|accessdate=2012-12-26 }}</ref> The giant helium-filled balloon is slowly drifting about 36 km above Antarctica. It was "[l]aunched on Tuesday (Dec. 25) from the National Science Foundation's Long Duration Balloon (LDB) facility ... This is the fifth and final mission for BLAST, short for the Balloon-borne Large-Aperture Submillimeter Telescope. ... "BLAST found lots of so-called dark cores in our own Milky Way — dense clouds of cold dust that are supposed to be stars-in-the-making. Based on the number of dark cores, you would expect our galaxy to spawn dozens of new stars each year on average. Yet, the galactic star formation rate is only some four solar masses per year." So why is the stellar birth rate in our Milky Way so low? Astronomers can think of two ways in which a dense cloud of dust is prevented from further contracting into a star: turbulence in the dust, or the collapse-impeding effects of magnetic fields. On its new mission, BLAST should find out which process is to blame. ... [The 1800-kilogram] stratospheric telescope will observe selected [[star-forming region]]s in the constellations Vela and Lupus."<ref name=Schilling>{{ cite web
|author=Govert Schilling
|title=NASA Launches Telescope-Toting Balloon from Antarctica on Christmas
|publisher=SPACE.com
|location=McMurdo Station
|month=December 26,
|year=2012
|url=http://news.yahoo.com/nasa-launches-telescope-toting-balloon-antarctica-christmas-164200686.html
|accessdate=2012-12-26 }}</ref>
{{clear}}
=Aircraft assisted launches=
"The '''Array of Low Energy X-ray Imaging Sensors''' ('''ALEXIS''') [[X-ray astronomy|X-ray]] telescopes feature curved mirrors whose multilayer coatings reflect and focus low-energy X-rays or extreme ultraviolet light the way [[w:optical telescope|optical telescope]]s focus visible light. ... The Launch was provided by the [[w:United States Air Force|United States Air Force]] Space Test Program on a [[w:Pegasus rocket|Pegasus]] Booster on April 25, 1993.<ref name=ALEXIA>{{ cite web
|title=ALEXIS satellite marks fifth anniversary of launch
|url=http://www.fas.org/spp/military/program/masint/98-062.html
|accessdate=17 August 2011
|publisher=Los Alamos National Laboratory
|date=23 April 1998 }}</ref>"<ref name=ALEXIS>{{ cite web
|title=Array of Low Energy X-ray Imaging Sensors, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 18,
|year=2011
|url=http://en.wikipedia.org/wiki/Array_of_Low_Energy_X-ray_Imaging_Sensors
|accessdate=2012-12-09 }}</ref>
=See also=
{{div col|colwidth=12em}}
* [[w:List of telescope parts and construction|List of telescope parts]]
* [[Radiation]]
* [[Radiation astronomy]]
* [[Radiation detectors]]
* [[Radiation satellites]]
{{Div col end}}
=References=
{{reflist|2}}
=Further reading=
=External links=
* [http://www.ajol.info/ African Journals Online]
* [http://www.bing.com/search?q=&go=&qs=n&sk=&sc=8-15&qb=1&FORM=AXRE Bing Advanced search]
* [http://books.google.com/ Google Books]
* [http://scholar.google.com/advanced_scholar_search?hl=en&lr= Google scholar Advanced Scholar Search]
* [http://www.iau.org/ International Astronomical Union]
* [http://www.jstor.org/ JSTOR]
* [http://www.lycos.com/ Lycos search]
* [http://nedwww.ipac.caltech.edu/ NASA/IPAC Extragalactic Database - NED]
* [http://nssdc.gsfc.nasa.gov/ NASA's National Space Science Data Center]
* [http://www.ncbi.nlm.nih.gov/sites/gquery NCBI All Databases Search]
* [http://www.ncbi.nlm.nih.gov/ncbisearch/ NCBI Site Search]
* [http://www.osti.gov/ Office of Scientific & Technical Information]
* [http://www.ncbi.nlm.nih.gov/pccompound PubChem Public Chemical Database]
* [http://www.questia.com/ Questia - The Online Library of Books and Journals]
* [http://online.sagepub.com/ SAGE journals online]
* [http://www.adsabs.harvard.edu/ The SAO/NASA Astrophysics Data System]
* [http://www.scirus.com/srsapp/advanced/index.jsp?q1= Scirus for scientific information only advanced search]
* [http://cas.sdss.org/astrodr6/en/tools/quicklook/quickobj.asp SDSS Quick Look tool: SkyServer]
* [http://simbad.u-strasbg.fr/simbad/ SIMBAD Astronomical Database]
* [http://nssdc.gsfc.nasa.gov/nmc/SpacecraftQuery.jsp Spacecraft Query at NASA.]
* [http://www.springerlink.com/ SpringerLink]
* [http://www.tandfonline.com/ Taylor & Francis Online]
* [http://heasarc.gsfc.nasa.gov/cgi-bin/Tools/convcoord/convcoord.pl Universal coordinate converter]
* [http://onlinelibrary.wiley.com/advanced/search Wiley Online Library Advanced Search]
* [http://search.yahoo.com/web/advanced Yahoo Advanced Web Search]
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