View source for Astronomy:Large Binocular Telescope

{{Short description|Telescope for optical astronomy}}
{{Infobox telescope}}
The '''Large Binocular Telescope''' ('''LBT''') is an optical telescope for astronomy located on {{convert|10700|ft|m|adj=on}} Mount Graham, in the Pinaleno Mountains of southeastern Arizona, United States. It is a part of the [[Astronomy:Mount Graham International Observatory|Mount Graham International Observatory]].

When using both 8.4&nbsp;m (330&nbsp;inch) wide mirrors, with centres 14.4 m apart, the LBT has the same light-gathering ability as an 11.8&nbsp;m (464&nbsp;inch) wide single circular telescope and the resolution of a 22.8&nbsp;m (897&nbsp;inch) wide one.<ref name="BBC">{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/7282385.stm |title=Giant telescope opens both eyes |access-date=2008-03-06 |work=BBC News | date=2008-03-06}}</ref>

The LBT mirrors individually are the joint second-[[Astronomy:List of largest optical reflecting telescopes|largest optical telescope]] in continental North America, next to the [[Astronomy:Hobby–Eberly Telescope|Hobby–Eberly Telescope]] in West Texas. It has the largest monolithic, or {{nowrap|non-segmented, mirror}} in an optical telescope.

Strehl ratios of 60–90% in the [[Physics:Infrared|infrared]] [[Physics:H band (infrared)|H band]] and 95% in the [[Physics:Infrared|infrared]] [[Physics:M band (infrared)|M band]] have been achieved by the LBT.<ref name="physorg.com"/>

== Project ==
The LBT was originally named the "Columbus Project." It is a joint project of these members: the Italian astronomical community represented by the Istituto Nazionale di Astrofisica, the [[Organization:University of Arizona|University of Arizona]], [[Organization:University of Minnesota|University of Minnesota]],<ref name="autogenerated1">{{cite web |url=http://www.nd.edu/~lumen/2007_04/FirstsciencefromtheLargeBinocularTelescope.shtml |title=First science from the Large Binocular Telescope |publisher=Nd.edu |date=2007-04-13 |access-date=2009-08-09 |url-status=dead |archive-url=https://web.archive.org/web/20090502024118/http://www.nd.edu/~lumen/2007_04/FirstsciencefromtheLargeBinocularTelescope.shtml |archive-date=2009-05-02 }}</ref> University of Notre Dame,<ref name="autogenerated1"/> [[Organization:University of Virginia|University of Virginia]],<ref name="autogenerated1" /> the LBT Beteiligungsgesellschaft in Germany ([[Organization:Max Planck Institute for Astronomy|Max Planck Institute for Astronomy]] in Heidelberg, Landessternwarte in Heidelberg, [[Organization:Leibniz Institute for Astrophysics Potsdam|Leibniz Institute for Astrophysics Potsdam]] (AIP), [[Organization:Max Planck Institute for Extraterrestrial Physics|Max Planck Institute for Extraterrestrial Physics]] in [[Place:Munich|Munich]] and [[Organization:Max Planck Institute for Radio Astronomy|Max Planck Institute for Radio Astronomy]] in [[Place:Bonn|Bonn]]); [[Organization:Ohio State University|Ohio State University]]<!--Wikipedians do not use "The" as part of Ohio State's name; it is considered a marketing gimmick, and routinely deleted.-->; and the Research Corporation for Science Advancement based in Tucson, Arizona, USA. The cost was around 100 million Euro.

The telescope design has two 8.4&nbsp;m (330&nbsp;inch) mirrors mounted on a common base, hence the name "binocular."<ref name="BBC" /> LBT takes advantage of [[Astronomy:Active optics|active]] and [[Astronomy:Adaptive optics|adaptive optics]], provided by Arcetri Observatory. The collecting area is two 8.4 meter aperture mirrors, which works out to about 111&nbsp;m<sup>2</sup> combined. This area is equivalent to an {{convert|11.8|m|in|adj=on|sp=us}} circular aperture, which would be greater than any other single telescope, but it is not comparable in many respects since the light is collected at a lower diffraction limit and is not combined in the same way. Also, an [[Astronomy:Interferometry|interferometric]] mode will be available, with a maximum baseline of {{convert|22.8|m|ft|sp=us}} for aperture synthesis imaging observations and a baseline of {{convert|15|m|ft|sp=us}} for nulling interferometry. This feature is along one axis with the LBTI instrument at wavelengths of 2.9–13 micrometres, which is the near infrared.<ref>{{Cite web|url=http://lbti.as.arizona.edu/LBTI-Main/Instrument.html|title=LBTI Instruments|access-date=24 June 2015|url-status=dead|archive-url=https://web.archive.org/web/20120310151556/http://lbti.as.arizona.edu/LBTI-Main/Instrument.html|archive-date=10 March 2012}}</ref>

The telescope was designed by a group of Italian firms, and assembled by Ansaldo in its Milanese plant.

=== Mountain controversy ===
[[File:LBT Pinaleno Mountains.40936.JPG|thumb|upright=1.25|LBT perched on an Arizona mountain]]

The choice of location sparked considerable local controversy, both from the San Carlos Apache Tribe, who view the mountain as sacred, and from environmentalists who contended that the observatory would cause the demise of an endangered subspecies of the American red squirrel, the [[Biology:Mount Graham red squirrel|Mount Graham red squirrel]]. Environmentalists and members of the tribe filed some forty lawsuits&nbsp;– eight of which went before a federal appeals court&nbsp;– but the project ultimately prevailed after an act of the United States Congress.

The telescope and mountain observatory survived two major forest fires in thirteen years, the more recent in the summer of 2017. Likewise the squirrels continue to survive. Some experts now believe their numbers fluctuate dependent upon nut harvest without regard to the observatory.<ref>
{{cite web
 |title       = The Mt. Graham Red Squirrel
 |website     = medusa.as.arizona.edu
 |date        = 2000-05-24
 |url         = http://medusa.as.arizona.edu/graham/envir.html
 |access-date  = 2010-04-25
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20080324012620/http://medusa.as.arizona.edu/graham/envir.html
 |archive-date = 2008-03-24
}}
</ref><ref>{{cite web
 | title= Mount Graham red squirrel fall 2005 count announced
 | publisher= Arizona Game and Fish Department
 | date= Nov 17, 2005
 | url= http://www.azgfd.gov/artman/publish/article_423.shtml
 | access-date= 2010-04-25
 | archive-url= https://web.archive.org/web/20100201074944/http://www.azgfd.gov/artman/publish/article_423.shtml
 | archive-date= 2010-02-01
 | url-status= dead
 }}</ref>

== First light ==
[[File:Large Binocular Telescope - November 2006.jpg|thumb|Dome during the day with doors closed]]
The telescope was dedicated in October 2004 and saw [[Astronomy:First light|first light]] with a single primary mirror on October 12, 2005, which viewed [[Astronomy:NGC 891|NGC 891]].<ref>{{cite web |title=LBT "First Light" image of NGC891 taken on October 12, 2005 |url=http://medusa.as.arizona.edu/lbto/first_light.htm |website=Large Binocular Telescope Observatory |via=medusa.as.arizona.edu |access-date=2010-04-25 |archive-url=https://web.archive.org/web/20081202105302/http://medusa.as.arizona.edu/lbto/first_light.htm |archive-date=2008-12-02 |url-status=dead}}</ref><ref>{{cite press release |title=Large Binoccular Telescope Successfully Achieves First Light |url=http://www.spaceref.com/news/viewpr.html?pid=18115 |via=spaceref.com |date=October 26, 2005 |access-date=2010-04-25}}</ref> The second primary mirror was installed in January 2006 and became fully operational in January 2008.<ref name="BBC"/> The first light with the second primary mirror was on September 18, 2006,{{Citation needed|date=June 2020}} and for the first and second together it was on January 11–12, 2008.<ref>{{cite press release |title=Large Binocular Telescope Achieves First Binocular Light |url=http://medusa.as.arizona.edu/lbto/firstbinocularlight_press_release.htm |date=2008-02-28 |publisher=Large Binocular Telescope Corporation |url-status=dead |archive-url=https://web.archive.org/web/20110725231212/http://medusa.as.arizona.edu/lbto/firstbinocularlight_press_release.htm |archive-date=2011-07-25 }}</ref>

The first binocular light images show three false-color renditions of the spiral galaxy [[Astronomy:NGC 2770|NGC 2770]]. The galaxy is 88 million light years from the Milky Way galaxy, a relatively close neighbor. The galaxy has a flat disk of stars and glowing gas tipped slightly toward Earth's [[Line-of-sight propagation|line of sight]].

The first image taken combined ultraviolet and green light, and emphasizes the clumpy regions of newly formed hot stars in the spiral arms. The second image combined two deep red colors to highlight the smoother distribution of older, cooler stars. The third image was a composite of ultraviolet, green and deep red light and shows the detailed structure of hot, moderate and cool stars in the galaxy. The cameras and images were produced by the Large Binocular Camera team, led by Emanuele Giallongo at the Rome Astrophysical Observatory.

In binocular [[Astronomy:Aperture synthesis|aperture synthesis]] mode LBT has a light-collecting area of 111 m<sup>2</sup>, equivalent to a single primary mirror {{convert|11.8|m|ft|adj=on|sp=us}} in diameter, and will combine light to produce the image sharpness equivalent to a single {{convert|22.8|m|ft|adj=on|sp=us}} telescope. However, this requires a beam combiner that was tested in 2008, but has not been a part of regular operations.<ref>{{Cite web|url=http://lbti.as.arizona.edu/LBTI-Main/Project.html|title=LBTI Project|url-status=dead|archive-url=https://web.archive.org/web/20100819102029/http://lbti.as.arizona.edu/LBTI-Main/Project.html|archive-date=2010-08-19}}</ref> It can take images with one side at 8.4 m aperture, or take two images of the same object using different instruments on each side of the telescope.

==Adaptive optics==
[[File:LBT 3.JPG|thumb|Interior looking down one of the primary mirrors]]
In the summer of 2010, the "First Light Adaptive Optics" (FLAO) – an [[Astronomy:Adaptive optics|adaptive optics]] system with a deformable [[Astronomy:Secondary mirror|secondary mirror]] rather than correcting atmospheric distortion further downstream in the optics – was inaugurated.<ref name="physorg.com">{{cite web|url=http://www.physorg.com/news195838118.html|title=Sharper than Hubble: Large Binocular Telescope achieves major breakthrough|work=Physorg.com |author=Max Planck Society |date=June 15, 2010}}</ref><ref name=lbtsharp/> Using one 8.4 m side, it surpassed Hubble sharpness (at certain light wavelengths), achieving a [[Engineering:Strehl ratio|Strehl ratio]] of 60–80% rather than the 20–30% of older adaptive optic systems, or the 1% typically achieved without adaptive optics for telescopes of this size.<ref name=lbtsharp>{{Cite web|url=http://spie.org/x40969.xml?ArticleID=x40969|title=Sharper than Hubble: Large Binocular Telescope achieves major breakthrough|access-date=18 June 2010|publisher=SPIE |author=Max Planck Society |date=18 June 2010}}</ref><ref name=mpialbt>{{cite web|url=http://www.mpia.de/Public/menu_q2.php?Aktuelles/PR/2010/PR100615/PR_100615_en.htm|title=Max-Planck-Institut für Astronomie|work=mpia.de}}</ref> Adaptive optics at a telescope's secondary (M2) was previously tested at [[Astronomy:MMT Observatory|MMT Observatory]] by the Arcetri Observatory and University of Arizona team.<ref>{{Cite web |author=Close |first=Laird |title=Adaptive Optics at the MMT and First Science Results |url=http://exoplanet.as.arizona.edu/~lclose/talks/ins/ESO_MMTAO_3 |url-status=dead |archive-url=https://web.archive.org/web/20150902085726/http://exoplanet.as.arizona.edu/~lclose/talks/ins/ESO_MMTAO_3 |archive-date=2 September 2015 |access-date=24 June 2015 |collaboration=Center for Astronomical Adaptive Optics team}}</ref>

== In the media ==
The telescope has made appearances on an episode of the Discovery Channel TV show ''Really Big Things'', National Geographic Channel ''Big, Bigger, Biggest'',<ref>{{cite web |website=National Geographic Channel |url= http://channel.nationalgeographic.com/channel/series/big-bigger-biggest |title=Big, Bigger, Biggest |archive-url=https://web.archive.org/web/20110822001704/http://channel.nationalgeographic.com/channel/series/big-bigger-biggest |archive-date=2011-08-22 |url-status=dead}}</ref> and the BBC program ''The Sky At Night''.{{citation needed|date=July 2020}} The BBC Radio 4 radio documentary ''The New Galileos'' covered the LBT and the [[Astronomy:James Webb Space Telescope|James Webb Space Telescope]].<ref>{{cite web |url= http://www.bbc.co.uk/programmes/b00k29vv |title=The New Galileos |last=Luck-Bake |first=Andrew |work=BBC |access-date=2009-05-14}}</ref>

==Discoveries and observations==
LBT, with the [[Astronomy:XMM-Newton|XMM-Newton]], was used to discover the [[Astronomy:Galaxy cluster|galaxy cluster]] [[Astronomy:2XMM J083026+524133|2XMM J083026+524133]] in 2008, over 7 billion light years away from [[Astronomy:Earth|Earth]].<ref>{{cite web |author=Baldwin |first=Emily |date=2008-08-27 |title=XMM discovers monster galaxy cluster |url=http://astronomynow.com/080827XMMdiscoversmonstergalaxycluster.html |access-date=2010-04-25 |publisher=Astronomynow.com}}</ref> In 2007 the LBT detected a 26th magnitude afterglow from the gamma ray burst [[Astronomy:GRB 070125|GRB 070125]].<ref>{{Cite web|url=http://www.nd.edu/~lumen/2007_04/FirstsciencefromtheLargeBinocularTelescope.shtml|title=First science from the Large Binocular Telescope|url-status=dead|archive-url=https://web.archive.org/web/20090502024118/http://www.nd.edu/~lumen/2007_04/FirstsciencefromtheLargeBinocularTelescope.shtml|archive-date=2009-05-02}}</ref>

In 2017, LBT observed the [[Astronomy:OSIRIS-REx|OSIRIS-REx]] spacecraft, an uncrewed asteroid sample return spacecraft, in space while it was en route.<ref>{{Cite news|url=https://www.nasa.gov/image-feature/goddard/2017/large-binocular-telescope-snags-first-glimpse-of-osiris-rex|title=Large Binocular Telescope Snags a Glimpse of NASA's OSIRIS-REx|last=Hille|first=Karl|date=2017-09-08|work=NASA|access-date=2018-10-20|language=en}}</ref>

==Instruments==
[[File:LBT Raid.jpg|thumb|Computer systems for LBT]]
[[File:LBT Linux.jpg|thumb|Computer workstation for LBT]]
Some current or planned LBT telescope instruments:<ref name="BBC"/>
* LBC – optical and near ultraviolet wide field prime focus cameras. One is optimized for the blue part of the optical spectrum and one for the red. (Both cameras operational)
* PEPSI – A high resolution and very high-resolution optical spectrograph and imaging polarimeter at the combined focus. (In development)
* MODS – two optical multi object and longslit spectrographs plus imagers. Capable of running in a single mirror or binocular mode. (MODS1 operational – MODS2 in integration on the mountain)
* LUCI – two [[Astronomy:Multi-Object Spectrometer|multi-object]] and [[Physics:Long-slit spectroscopy|longslit]] infrared spectrographs plus imagers, one for each side (associated with one of the 8m mirrors) of the telescope. The imager has 2 cameras and can observe in both seeing-limited and diffraction-limited (with adaptive optics) modes. End of commissioning and hand over to the LBTO was in 2018.{{citation needed|date=November 2018}}
* LINC/Nirvana – wide-field interferometric imaging with adaptive optics at the combined focus (in commissioning).
* LBTI/LMIRCAM – 2.9 to 5.2 micron Fizeau imaging and medium resolution grism spectroscopy at the combined focus.
* LBTI/NOMIC – N band nulling imager for the study of protoplanetary and debris disks at the combined focus. (In commissioning phase – first stabilization of the fringes in December 2013)
* FLAO – first light adaptive optics to correct atmospheric distortion
* [[Engineering:ARGOS (optics system)|ARGOS]] – multiple laser guide star unit capable of supporting ground layer or multi conjugate adaptive optics. End of commissioning and handover to LBTO was in 2018.<ref>{{Cite web|url=http://www.lbto.org/LBT%20Website%20General%20Public/Advanced%20Rayleigh%20guided%20Ground%20layer%20adaptive%20Optics%20System.htm |title=Advanced Rayleigh guided Ground layer adaptive Optics System |access-date=24 June 2015 |url-status=dead |archive-url=https://web.archive.org/web/20131102160628/http://www.lbto.org/LBT%20Website%20General%20Public/Advanced%20Rayleigh%20guided%20Ground%20layer%20adaptive%20Optics%20System.htm |archive-date= 2 November 2013 }}</ref>

===LUCI===
LUCI (originally LUCIFER: '''L'''arge Binocular Telescope Near-infrared Spectroscopic '''U'''tility with '''C'''amera and '''I'''ntegral '''F'''ield Unit for '''E'''xtragalactic '''R'''esearch) is the near-infrared instrument for the LBT.<ref name=planck>{{cite web |url=http://www.mpe.mpg.de/ir/lucifer/ |title=LUCI – A Near-Infrared Camera & Spectrograph for the LBT |publisher=Max Planck Institute for Extraterrestrial Physics |access-date=5 July 2016}}</ref><ref>{{cite web |first=Rebecca |last=Boyle |title = LUCIFER instrument helps astronomers to see through darkness observable remote MOST objects |date=23 April 2010 |url=http://www.popsci.com/science/article/2010-04/devil-named-telescope-helps-astronomers-see-through-darkness|access-date=29 September 2015}}</ref>
<ref>{{cite web |url=http://www.astronomy.com/news/2010/04/lucifer-allows-astronomers-to-watch-stars-being-born |title=LUCIFER allows astronomers to watch stars being born |publisher=Astronomy Magazine – Kalmbach Publishing |access-date=5 July 2016 |date=23 April 2010 |author=University of Arizona}}</ref> The name of the instrument was changed to LUCI in 2012. LUCI operates in the 0.9–2.5&nbsp;µm spectral range using a 2048 x 2048 element Hawaii-2RG detector array from Teledyne and provides imaging and spectroscopic capabilities in seeing- and diffraction-limited modes. In its focal plane area, long-slit and multi-slit masks can be installed for single-object and multi-object spectroscopy. A fixed collimator produces an image of the entrance aperture in which either a mirror (for imaging) or a grating can be positioned. Three camera optics with numerical apertures of 1.8, 3.75 and 30 provide image scales of 0.25, 0.12, and 0.015 arcsec/detector element for wide field, seeing-limited and diffraction-limited observations. LUCI is operated at cryogenic temperatures, and is therefore enclosed in a [[Physics:Cryostat|cryostat]] of 1.6 m diameter and 1.6 m height, and cooled to about −200&nbsp;°C by two closed-cycle coolers.<ref name=planck/>

==LBTO collaboration==
{{comparison optical telescope primary mirrors.svg|550px}}
Partners in the LBT project<ref>{{Cite web|url=http://www.lbto.org/lbt-collaboration.html|title=Project partners|access-date=20 Jan 2016}}</ref>
* Arizona, USA (25%) – AZ
** [[Organization:University of Arizona|The University of Arizona]] (Headquarters) – Tucson
** [[Organization:Arizona State University|Arizona State University]] – Tempe
** [[Organization:Northern Arizona University|Northern Arizona University]] – Flagstaff
* Germany (25%) – LBTB
** [[Organization:Heidelberg-Königstuhl State Observatory|Landessternwarte]] – Heidelberg
** [[Organization:Leibniz Institute for Astrophysics Potsdam|Leibniz-Institut für Astrophysik Potsdam]] – Potsdam
** [[Organization:Max Planck Institute for Astronomy|Max-Planck-Institut für Astronomie]] – Heidelberg
** [[Organization:Max Planck Institute for Extraterrestrial Physics|Max-Planck-Institut für Extraterrestrische Physik]] – Munich
** [[Organization:Max Planck Institute for Radio Astronomy|Max-Planck-Institut für Radioastronomie]] – Bonn
* Italy (25%) – INAF
** [[Organization:INAF|Istituto Nazionale di Astrofisica]]
* Research Corporation for Science Advancement, USA (12.5%) – RC
** The [[Organization:Ohio State University|Ohio State University]] – Ohio
** University of Notre Dame – Indiana
** [[Organization:University of Minnesota|University of Minnesota]] – Minnesota
** [[Organization:University of Virginia|University of Virginia]] – Virginia
* The [[Organization:Ohio State University|Ohio State University]], Ohio, USA (12.5%) – OSU

== Other MGIO facilities ==
* Mount Graham [[Astronomy:Heinrich Hertz Submillimeter Telescope|Submillimeter Telescope]]
* [[Engineering:Vatican Advanced Technology Telescope|Vatican Advanced Technology Telescope]]

== See also ==
{{div col |colwidth=22em}}
* [[Astronomy:Extremely large telescope|Extremely large telescope]]
* List of astronomical interferometers at visible and infrared wavelengths
* [[Astronomy:List of largest optical reflecting telescopes|List of largest optical reflecting telescopes]]
* [[Astronomy:List of largest optical telescopes historically|List of largest optical telescopes historically]]
* List of largest optical telescopes in the continental United States
* [[Astronomy:Lists of telescopes|Lists of telescopes]]
* [[Astronomy:Mount Graham International Observatory|Mount Graham International Observatory]]
* [[Astronomy:Navigator Program|Navigator Program]]
* Richard Green (astronomer)
* Safford, Arizona
{{div col end}}

== References ==
{{reflist|30em}}

== External links ==
* Website of the [http://www.lbto.org/ LBT]
* [https://www.as.arizona.edu/lbt-interferometer-lbti LBTI] and [https://www.as.arizona.edu/large-binocular-telescope LBT] at [[Organization:University of Arizona|University of Arizona]]
* [http://www.mpia.de/LINC/ Linc-Nirvana] at the [[Organization:Max Planck Institute for Astronomy|MPIA]]
<!---
* [https://web.archive.org/web/20070803104713/http://wiki.lbto.arizona.edu/twiki/bin/view/Observing/WebHome LBT Observer's Wiki]
* [https://web.archive.org/web/20071031110055/http://lbc.mporzio.astro.it/ LBT Large Binocular Camera]
--->
* [http://www.mpia.de/homes/LBTBWEB/index.html LBT Beteiligungsgesellschaft]
* [https://pepsi.aip.de PEPSI] at the [[Organization:Leibniz Institute for Astrophysics Potsdam|AIP]]
* [http://www.eac.edu/DISCOVERYPARK/mgio.shtm Discovery Park] – Guided MGIO tours for the public
* [https://web.archive.org/web/20110719115417/http://www.mpia.de/Public/Aktuelles/PR/2010/PR100615/PR100615_2en_gr.jpg AO LBT comparison]
* The [https://www.youtube.com/watch?v=m8RqFGvH4M0 Big Bigger Biggest program] featured the LBT (50:10, YouTube video)
* {{Skeptoid | id=4729 | number=729 | title= The LUCIFER Telescope Conspiracy| date= May 26, 2020| quote= | access-date=}}

{{Astronomy navbox}}
{{Jet Propulsion Laboratory}}

[[Category:Optical telescopes]]
[[Category:Astronomical observatories in Arizona]]
[[Category:Interferometric telescopes]]
[[Category:Double telescopes]]

{{Sourceattribution|Large Binocular Telescope}}