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Large Binocular Telescope

Coordinates:32°42′05″N109°53′21″W/ 32.701308°N 109.889064°W/32.701308; -109.889064
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"LUCIFER" redirects here. For other uses, seeLucifer (disambiguation).

Large Binocular Telescope
Alternative namesFirst LightEdit this at Wikidata
Part ofMount Graham International Observatory
Steward ObservatoryEdit this on Wikidata
Location(s)Mount Graham,Graham County,Arizona
Coordinates32°42′05″N109°53′21″W/ 32.701308°N 109.889064°W/32.701308; -109.889064Edit this at Wikidata
Observatory codeG83Edit this on Wikidata
Altitude3,221 m (10,568 ft)Edit this at Wikidata
First light12 October 2005Edit this on Wikidata
Telescope styleoptical telescope
double telescopeEdit this on Wikidata
Diameter8.4 m (27 ft 7 in)Edit this at Wikidata
Collecting area111 m2(1,190 sq ft)Edit this at Wikidata
Focal length9.6 m (31 ft 6 in)Edit this at Wikidata
Mountingaltazimuth mountEdit this on Wikidata
Websitewww.lbto.orgEdit this at Wikidata
Large Binocular Telescope is located in the United States
Large Binocular Telescope
Location of Large Binocular Telescope
Related media on Commons
[edit on Wikidata]

TheLarge Binocular Telescope(LBT) is an optical telescope for astronomy located on 10,700-foot (3,300 m)Mount Graham,in thePinaleno Mountainsof southeasternArizona,United States. It is a part of theMount Graham International Observatory.

When using both 8.4 m (330 inch) wide mirrors, with centres 14.4 m apart, the LBT has the same light-gathering ability as an 11.8 m (464 inch) wide single circular telescope and the resolution of a 22.8 m (897 inch) wide one.[1]

The LBT mirrors individually are the joint second-largest optical telescopein continental North America, next to theHobby–Eberly TelescopeinWest Texas.It has the largest monolithic, ornon-segmented,mirrorin an optical telescope.

Strehl ratiosof 60–90% in theinfraredH bandand 95% in theinfraredM bandhave been achieved by the LBT.[2]

Project[edit]

The LBT was originally named the "Columbus Project." It is a joint project of these members: the Italian astronomical community represented by theIstituto Nazionale di Astrofisica,theUniversity of Arizona,University of Minnesota,[3]University of Notre Dame,[3]University of Virginia,[3]the LBT Beteiligungsgesellschaft in Germany (Max Planck Institute for Astronomyin Heidelberg,Landessternwartein Heidelberg,Leibniz Institute for Astrophysics Potsdam(AIP),Max Planck Institute for Extraterrestrial PhysicsinMunichandMax Planck Institute for Radio AstronomyinBonn);Ohio State University;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 m (330 inch) mirrors mounted on a common base, hence the name "binocular."[1]LBT takes advantage ofactiveandadaptive optics,provided byArcetri Observatory.The collecting area is two 8.4 meter aperture mirrors, which works out to about 111 m2combined. This area is equivalent to an 11.8-meter (460 in) 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, aninterferometricmode will be available, with a maximum baseline of 22.8 meters (75 ft) for aperture synthesis imaging observations and a baseline of 15 meters (49 ft) 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.[4]

The telescope was designed by a group of Italian firms, and assembled byAnsaldoin itsMilaneseplant.

Mountain controversy[edit]

LBT perched on an Arizona mountain

The choice of location sparked considerable local controversy, both from theSan 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, theMount Graham red squirrel.Environmentalists and members of the tribe filed some forty lawsuits – eight of which went before a federal appeals court – but the project ultimately prevailed after an act of theUnited 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.[5][6]

First light[edit]

Dome during the day with doors closed

The telescope was dedicated in October 2004 and sawfirst lightwith a single primary mirror on October 12, 2005, which viewedNGC 891.[7][8]The second primary mirror was installed in January 2006 and became fully operational in January 2008.[1]The first light with the second primary mirror was on September 18, 2006,[citation needed]and for the first and second together it was on January 11–12, 2008.[9]

The first binocular light images show three false-color renditions of the spiral galaxyNGC 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'sline 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 binocularaperture synthesismode LBT has a light-collecting area of 111 m2,equivalent to a single primary mirror 11.8-meter (39 ft) in diameter, and will combine light to produce the image sharpness equivalent to a single 22.8-meter (75 ft) telescope. However, this requires a beam combiner that was tested in 2008, but has not been a part of regular operations.[10]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[edit]

Interior looking down one of the primary mirrors

In the summer of 2010, the "First Light Adaptive Optics" (FLAO) – anadaptive opticssystem with a deformablesecondary mirrorrather than correcting atmospheric distortion further downstream in the optics – was inaugurated.[2][11]Using one 8.4 m side, it surpassed Hubble sharpness (at certain light wavelengths), achieving aStrehl ratioof 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.[11][12]Adaptive optics at a telescope's secondary (M2) was previously tested atMMT Observatoryby the Arcetri Observatory and University of Arizona team.[13]

In the media[edit]

The telescope has made appearances on an episode of theDiscovery ChannelTVshowReally Big Things,National Geographic ChannelBig, Bigger, Biggest,[14]and theBBCprogramThe Sky At Night.[citation needed]TheBBC Radio 4radio documentaryThe New Galileoscovered the LBT and theJames Webb Space Telescope.[15]

Discoveries and observations[edit]

LBT, with theXMM-Newton,was used to discover thegalaxy cluster2XMM J083026+524133in 2008, over 7 billion light years away fromEarth.[16]In 2007 the LBT detected a 26th magnitude afterglow from the gamma ray burstGRB 070125.[17]

In 2017, LBT observed theOSIRIS-RExspacecraft, an uncrewed asteroid sample return spacecraft, in space while it was en route.[18]

Instruments[edit]

Computer systems for LBT
Computer workstation for LBT

Some current or planned LBT telescope instruments:[1]

  • 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 – twomulti-objectandlongslitinfrared 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]
  • LINC/Nirvana – wide-field interferometric imaging with adaptive optics at the combined focus (in commissioning).
  • LBTI/LMIRCAM – 2.9 to 5.2 micronFizeauimaging 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
  • 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.[19]

LUCI[edit]

LUCI (originally LUCIFER:Large Binocular Telescope Near-infrared SpectroscopicUtility withCamera andIntegralField Unit forExtragalacticResearch) is the near-infrared instrument for the LBT.[20][21] [22]The name of the instrument was changed to LUCI in 2012. LUCI operates in the 0.9–2.5 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 acryostatof 1.6 m diameter and 1.6 m height, and cooled to about −200 °C by two closed-cycle coolers.[20]

LBTO collaboration[edit]

Comparison of nominal sizes of apertures of the Large Binocular Telescope and some notable optical telescopes

Partners in the LBT project[23]

Other MGIO facilities[edit]

See also[edit]

References[edit]

  1. ^abcd"Giant telescope opens both eyes".BBC News.March 6, 2008.Retrieved2008-03-06.
  2. ^abMax Planck Society (June 15, 2010)."Sharper than Hubble: Large Binocular Telescope achieves major breakthrough".Physorg.
  3. ^abc"First science from the Large Binocular Telescope".Nd.edu. April 13, 2007. Archived fromthe originalon 2009-05-02.Retrieved2009-08-09.
  4. ^"LBTI Instruments".Archived fromthe originalon 2012-03-10.Retrieved2015-06-24.
  5. ^ "The Mt. Graham Red Squirrel".medusa.as.arizona.edu.May 24, 2000. Archived fromthe originalon 2008-03-24.Retrieved2010-04-25.
  6. ^"Mount Graham red squirrel fall 2005 count announced".Arizona Game and Fish Department. November 17, 2005. Archived fromthe originalon 2010-02-01.Retrieved2010-04-25.
  7. ^"LBT" First Light "image of NGC891 taken on October 12, 2005".Large Binocular Telescope Observatory.Archived fromthe originalon 2008-12-02.Retrieved2010-04-25– via medusa.as.arizona.edu.
  8. ^"Large Binoccular Telescope Successfully Achieves First Light"(Press release). October 26, 2005.Retrieved2010-04-25– via spaceref.
  9. ^"Large Binocular Telescope Achieves First Binocular Light"(Press release). Large Binocular Telescope Corporation. February 28, 2008. Archived fromthe originalon 2011-07-25.
  10. ^"LBTI Project".Archived fromthe originalon 2010-08-19.
  11. ^abMax Planck Society (June 18, 2010)."Sharper than Hubble: Large Binocular Telescope achieves major breakthrough".SPIE.Retrieved2010-06-18.
  12. ^"Max-Planck-Institut für Astronomie".mpia.de.
  13. ^Close, Laird; et al. (Center for Astronomical Adaptive Optics team)."Adaptive Optics at the MMT and First Science Results".Archived fromthe originalon 2015-09-02.Retrieved2015-06-24.
  14. ^"Big, Bigger, Biggest".National Geographic Channel.Archived fromthe originalon 2011-08-22.
  15. ^Luck-Bake, Andrew."The New Galileos".BBC.Retrieved2009-05-14.
  16. ^Baldwin, Emily (August 27, 2008)."XMM discovers monster galaxy cluster".Astronomynow.Retrieved2010-04-25.
  17. ^"First science from the Large Binocular Telescope".Archived fromthe originalon 2009-05-02.
  18. ^Hille, Karl (September 8, 2017)."Large Binocular Telescope Snags a Glimpse of NASA's OSIRIS-REx".NASA.Retrieved2018-10-20.
  19. ^"Advanced Rayleigh guided Ground layer adaptive Optics System".Archived fromthe originalon 2013-11-02.Retrieved2015-06-24.
  20. ^ab"LUCI – A Near-Infrared Camera & Spectrograph for the LBT".Max Planck Institute for Extraterrestrial Physics.Retrieved2016-07-05.
  21. ^Boyle, Rebecca (April 23, 2010)."LUCIFER instrument helps astronomers to see through darkness observable remote MOST objects".Retrieved2015-09-29.
  22. ^University of Arizona (April 23, 2010)."LUCIFER allows astronomers to watch stars being born".Astronomy Magazine – Kalmbach Publishing.Retrieved2016-07-05.
  23. ^"Project partners".Retrieved2016-01-20.

External links[edit]

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