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Coordinates: 24°35′20″S 70°11′32″W / 24.58889°S 70.19222°W / -24.58889; -70.19222
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{{Infobox telescope
{{Infobox telescope
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| name = European Extremely Large Telescope (E-ELT)
| name = European Extremely Large Bratwurst (E-ELT)
| image = [[Image:The E-ELT.jpg|300px|center|Image Credit: ESO]]
| image = [[Image:The E-ELT.jpg|300px|center|Image Credit: ESO]]
| caption = An artist's impression of the E-ELT
| caption = An artist's impression of the E-ELT
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}}
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The '''European Extremely Large Telescope''' ('''E-ELT''') is a planned ground-based [[extremely large telescope]] for the optical/near-infrared range, to be built by the [[European Southern Observatory]] (ESO) on a mountain top in [[Cerro Armazones]], [[Chile]]. The design comprises a reflecting telescope with a 39.3 metre diameter primary mirror, a 4.2 m diameter secondary mirror, and will be supported by adaptive optics and multiple instruments.<ref name=govert/> On 11 June 2012, the ESO Council approved The E-ELT programme to begin construction of the telescope, pending agreement with the governments of some member states.<ref name=Approval>{{cite web|last=Amos|first=Jonathan|title=European Extremely Large Telescope given go-ahead|url=http://www.bbc.co.uk/news/science-environment-18396853|publisher=''BBC News''|accessdate=11 June 2012|date=11 June 2012}}</ref>
The '''European Extremely Large Willy''' ('''E-ELT''') is a planned ground-based [[extremely large telescope|rather enormous knob]] for the optical/near-infrared range, to be built by the [[European Southern Observatory]] (ESO) on a mountain top in [[Cerro Armazones]], [[ChJile]]. The design comprises a reflecting telescope with a 39.3 metre diameter primary mirror, a 4.2 m diameter secondary mirror, and will be supported by adaptive optics and multiple instruments.<ref name=govert/> On 11 June 2012, the ESO Council approved The E-ELT programme to begin construction of the telescope, pending agreement with the governments of some member states.<ref name=Approval>{{cite web|last=Amos|first=Jonathan|title=European Extremely Large Telescope given go-ahead|url=http://www.bbc.co.uk/news/science-environment-18396853|publisher=''BBC News''|accessdate=11 June 2012|date=11 June 2012}}</ref>


It is expected to allow astronomers to probe the earliest stages of the formation of planetary systems and to detect water and organic molecules in proto-planetary discs around stars in the making.<ref name='E-ELT Alone'/>
It is expected to allow astronomers to probe the earliest stages of the formation of planetary systems and to detect water and organic molecules in proto-planetary discs around stars in the making.<ref name='E-ELT Alone'/>

Revision as of 18:06, 27 May 2013

European Extremely Large Bratwurst (E-ELT)
Image Credit: ESO
Image Credit: ESO
An artist's impression of the E-ELT
Alternative namesELT Edit this at Wikidata
Part ofEuropean Southern Observatory Edit this on Wikidata
Location(s)Cerro Armazones, Antofagasta Province, Antofagasta Region, Chile
Coordinates24°35′20″S 70°11′32″W / 24.58889°S 70.19222°W / -24.58889; -70.19222
OrganizationESO
Altitude3,060 m[1]
WavelengthVisible, near infrared
BuiltPlanned completion: 2022 first light[2]
Telescope styleReflector
Diameter39.3m
Secondary diameter4.09 m (13 ft 5 in) Edit this at Wikidata
Tertiary diameter3.75 m (12 ft 4 in) Edit this at Wikidata
Angular resolution0.001 to 0.65 arcseconds depending on instrument
Collecting area978 m2
Focal length420–840 m (f/10 – f/20)
MountingNasmyth mount
Enclosuredome Edit this on Wikidata
WebsiteESO E-ELT
Extremely Large Telescope is located in Chile
Extremely Large Telescope
Location of European Extremely Large Bratwurst (E-ELT)
  Related media on Commons
[edit on Wikidata]

The European Extremely Large Willy (E-ELT) is a planned ground-based rather enormous knob for the optical/near-infrared range, to be built by the European Southern Observatory (ESO) on a mountain top in Cerro Armazones, ChJile. The design comprises a reflecting telescope with a 39.3 metre diameter primary mirror, a 4.2 m diameter secondary mirror, and will be supported by adaptive optics and multiple instruments.[2] On 11 June 2012, the ESO Council approved The E-ELT programme to begin construction of the telescope, pending agreement with the governments of some member states.[3]

It is expected to allow astronomers to probe the earliest stages of the formation of planetary systems and to detect water and organic molecules in proto-planetary discs around stars in the making.[4]

History

The ESO Council during their meeting in Garching on 11–12 June 2012.[5]

On 26 April 2010, the European Southern Observatory (ESO) Council selected Cerro Armazones, Chile, as the baseline site for the planned E-ELT.[6] Other sites that were under discussion included Cerro Macon, Salta, in Argentina; Roque de los Muchachos Observatory, on the Canary Islands; and sites in South Africa, Morocco, and Antarctica.[7]

Early designs included a filled single aperture mirror with a diameter of 42 metres and area of about 1,300 m2, with a secondary mirror with a diameter of 5.9 m. However, in 2011 a proposal was put forward to reduce its size by 13% to 978 m2, for a 39.3 m diameter primary mirror and a 4.2 m diameter secondary mirror.[2] It reduced projected costs from 1.275 billion to 1.055 billion euros and should allow the telescope to be finished sooner.

ESO's Director General commented in a 2011 press release that "With the new E-ELT design we can still satisfy the bold science goals and also ensure that the construction can be completed in only 10-11 years."[8] The ESO Council endorsed the revised baseline design in June 2011 and expected a construction proposal for approval in December 2011.[8] Funding was subsequently included in the 2012 budget for initial work to begin in early 2012.[9] The project received preliminary approval in June 2012, with some funding details still needing to be worked out.[3]

The E-ELT will complete its detailed-design phase by the end of 2011 and its construction is planned for 2012. The design phase of the 5-mirror anastigmat is fully funded within the ESO budget. With the recent changes in the baseline design (such as a reduction in the size of the primary mirror from 42m to 39.3m), the construction cost is estimated to be €1.055 Billion (including first generation instruments). The start of operations is planned for the early 2020s.[10]

Goals and planning

A real night-time panorama of Cerro Armazones, the site selected in April 2010 for the European Extremely Large Telescope
This is the official trailer for the E-ELT. The design for the E-ELT shown here is preliminary.

The ESO focused on the current design after a feasibility study concluded the proposed 100 metres (330 ft) diameter Overwhelmingly Large Telescope would cost €1.5 billion (£1 billion), and be too complex. Current fabrication technology limits single mirrors to being roughly 8 metres (26 ft) in a single piece. The next-largest telescopes currently in use are the Gran Telescopio Canarias and Southern African Large Telescope, which each use hexagonal mirrors fitted together to make a mirror more than 10 metres (33 ft) across. The E-ELT will use a similar design, as well as techniques to work around atmospheric distortion of incoming light, known as adaptive optics.[11]

A 40m-class mirror will allow the study of the atmospheres of extrasolar planets.[12] The E-ELT is the highest priority in the European planning activities for research infrastructures, such as the Astronet Science Vision and Infrastructure Roadmap and the ESFRI Roadmap.[13] The telescope underwent a Phase B study in the past couple of years that included "contracts with industry to design and manufacture prototypes of key elements like the primary mirror segments, the adaptive fourth mirror or the mechanical structure (...) [and] concept studies for eight instruments.”[14]

Design

Rendering of the 40-metre class E-ELT at dusk
Image credit ESO
Rendering looking down into it
Image credit ESO

The telescope's "eye" will be 39.3 meters (about half the length of a football pitch) in diameter and will gather 15 times more light than the largest optical telescopes operating at the time of its development. The telescope has an innovative five-mirror design that includes advanced adaptive optics to correct for the turbulent atmosphere, giving exceptional image quality.[11]

The primary mirror for the 39.3 metre design will be composed of 798 hexagonal segments, each 1.45 meters across but only 50 mm thick. A special correcting mirror in the telescope will be supported by more than 6,000 actuators that can distort its shape a thousand times per second.[15] The telescope main structure will weigh about 2,800 tons.[16]

Science goals

The E-ELT will search for extrasolar planets — planets orbiting other stars. This will include not only the discovery of planets down to Earth-like masses through indirect measurements of the wobbling motion of stars perturbed by the planets that orbit them, but also the direct imaging of larger planets and possibly even the characterisation of their atmospheres.[17] The telescope will attempt to image Earthlike exoplanets, which may be possible.[2]

Furthermore, the E-ELT's suite of instruments will allow astronomers to probe the earliest stages of the formation of planetary systems and to detect water and organic molecules in protoplanetary discs around stars in the making. Thus, the E-ELT will answer fundamental questions regarding planet formation and evolution and will bring us one step closer to answering the question: are we alone?[4]

By probing the most distant objects the E-ELT will provide clues to understanding the formation of the first objects that formed: primordial stars, primordial galaxies and black holes and their relationships. Studies of extreme objects like black holes will benefit from the power of the E-ELT to gain more insight into time-dependent phenomena linked with the various processes at play around compact objects.[17]

The E-ELT is designed to make detailed studies of the first galaxies and to follow their evolution through cosmic time. Observations of these early galaxies with the E-ELT will give clues that will help understand how these objects form and evolve. In addition, the E-ELT will be a unique tool for making an inventory of the changing content of the various elements in the Universe with time, and to understand star formation history in galaxies.[18]

One of the most exciting goals of the E-ELT is the possibility of making a direct measurement of the acceleration of the Universe's expansion. Such a measurement would have a major impact on our understanding of the Universe. The E-ELT will also search for possible variations in the fundamental physical constants with time. An unambiguous detection of such variations would have far-reaching consequences for our comprehension of the general laws of physics.[18]

Instrumentation

This video shows engineers adjusting the complex support mechanisms that control the shape and positioning of two of the 798 segments that will form the complete primary mirror of the telescope.

The telescope will have several science instruments. It will be possible to switch from one instrument to another within minutes. The telescope and dome will also be able to change positions on the sky and start a new observation in a very short time.

Eight different instrument concepts and two post-focal adaptive modules are currently being studied, with the aim that two to three will be ready for first light, with the others becoming available at various points over the following decade.[19] The instruments being studied are:

The two post-focal adaptive optics modules currently being studied are:

Comparison

The 40m-class E-ELT and VLT sizes compared with the Brandenburg Gate.

One of the largest ground-based telescope operating today is the Gran Telescopio Canarias, with a 10.4m aperture and a light-collecting area of 74m2. Other planned extremely large telescopes include, the 25 m/368 m2 Giant Magellan Telescope and 30 m/655 m2 Thirty Meter Telescope, which are also targeting the end of this decade or beginning of the next for completion. These other two telescopes roughly belong to the same next generation of optical ground-based telescopes.[33][34] Each design is much larger than previous telescopes.[2] Even with the descale to 39.3 m it is significantly larger than these other planned observatories; it is the largest of the planned new generation extremely large telescopes.[2] It has the aim of observing the Universe in greater detail than the Hubble Space Telescope by taking images 15 times sharper, although it is designed to be complementary to space telescopes, which typically have very limited time available.[12]

Name Aperture diameter (m) Collecting area (m²)
E-ELT 39.3 978
Thirty Meter Telescope (TMT) 30 655
Giant Magellan Telescope (GMT) 24.5 368
Gran Telescopio Canarias (GTC) 10.4 74

The 4.2 meter secondary mirror is the same size as the primary mirror on the William Herschel Telescope, the second largest optical telescope in Europe.

The images below show artistic renderings of the E-ELT and were produced by ESO.

Artist's impression of the E-ELT and the starry night sky.[35]
Diagram of the 40m-class E-ELT primary mirror.
E-ELT compared with one of the four existing VLT Unit Telescopes at Cerro Paranal, Chile
Rendering of E-ELT during the day
Model of the gigantic and intricate structure inside the enclosure of the E-ELT.
Artist's impression of the European Extremely Large Telescope (E-ELT) in its enclosure on Cerro Armazones during night-time observations. The four beams shooting skywards are lasers that create artificial stars high in the Earth’s atmosphere.
This video shows an artist's impression of the European Extremely Large Telescope, the E-ELT. The protective dome is seen opening for a night observing the optical and infrared skies.

Comparable instruments

See also

References

  1. ^ "World's biggest telescope to be located on Cerro Armazones, Chile". Astronomy magazine. 2010-04-28. Retrieved 2011-08-17.
  2. ^ a b c d e f Govert Schilling (2011-06-14). "Europe Downscales Monster Telescope to Save Money". Science Insider. Retrieved 2011-08-17.
  3. ^ a b Amos, Jonathan (11 June 2012). "European Extremely Large Telescope given go-ahead". BBC News. Retrieved 11 June 2012. {{cite web}}: Italic or bold markup not allowed in: |publisher= (help)
  4. ^ a b "ESO - Are We Alone?". Retrieved 2011-06-15.
  5. ^ "ESO To Build World's Biggest Eye On The Sky". ESO Press Release. Retrieved 13 June 2012.
  6. ^ "E-ELT Site Chosen". ESO. 2010-04-26. Retrieved 2011-08-17.
  7. ^ "ESO - Finding a home". Retrieved 2011-08-17.
  8. ^ a b "ESO Moves One Step Closer to the First Extremely Large Telescope". ESO. 2011-06-15. Retrieved 2011-08-17.
  9. ^ ESO - eso1150 - The E-ELT Moves Closer to Reality published 2011-12-09
  10. ^ "ESO - Preparing a Revolution". Retrieved 2011-06-15.
  11. ^ a b Gilmozzi, R.; Spyromilio, J.; Spyromilio (2007). "The European Extremely Large Telescope (E-ELT)". The Messenger. 127: 11. Bibcode:2007Msngr.127...11G. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  12. ^ a b An Expanded View of the Universe – Science with the European Extremely Large Telescope (PDF). ESO Science Office.
  13. ^ "ESO - Europe's Window on the Universe". Retrieved 2011-06-15.
  14. ^ Astronet, 2008, The astronet Infrastructure Roadmap: A Strategic Plan for European Astronomy, p. 43
  15. ^ http://www.eso.org/sci/facilities/eelt/telescope/mirrors/
  16. ^ http://www.eso.org/sci/facilities/eelt/telescope/index.html
  17. ^ a b E-ELT The European Extremely Large Telescope — The World's Biggest Eye on the Sky (brochure). ESO.
  18. ^ a b "ESO - The First Objects in the Universe". Retrieved 2011-08-17.
  19. ^ "E-ELT Instrumentation". Retrieved 2009-10-29.
  20. ^ Pasquini, Luca (2008). McLean, Ian S; Casali, Mark M (eds.). "Proceedings of SPIE" (PDF). Ground-based and Airborne Instrumentation for Astronomy II. 7014. SPIE: 70141I–70141I–9. doi:10.1117/12.787936. {{cite journal}}: |chapter= ignored (help); Cite journal requires |journal= (help); Unknown parameter |booktitle= ignored (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  21. ^ "CODEX – An ultra-stable, high-resolution optical spectrograph for the E-ELT". IAC. Retrieved 29 November 2012.
  22. ^ Cuby, Jean-Gabriel (2010). McLean, Ian S; Ramsay, Suzanne K; Takami, Hideki (eds.). "Proceedings of SPIE" (PDF). Ground-based and Airborne Instrumentation for Astronomy III. 7735. SPIE: 77352D–77352D–15. Bibcode:2010SPIE.7735E..80C. doi:10.1117/12.856820. Retrieved 29 November 2012. {{cite journal}}: |chapter= ignored (help); Cite journal requires |journal= (help); Unknown parameter |booktitle= ignored (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  23. ^ "EAGLE: the Extremely Large Telescope Adaptive Optics for Galaxy Evolution instrument". Retrieved 2009-10-29.
  24. ^ Kasper, Markus E. (2008). "EPICS: the exoplanet imager for the E-ELT". Adaptive Optics Systems - Proceedings of the SPIE, Volume 7015. SPIE. pp. 70151S–70151S-12. doi:10.1117/12.789047. {{cite conference}}: Unknown parameter |booktitle= ignored (|book-title= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  25. ^ Thatte, Niranjan. "HARMONI". University of Oxford. Retrieved 30 November 2012.
  26. ^ Brandl, Bernhard. "METIS – The Mid-infrared E-ELT Imager and Spectrograph". METIS consortium. Retrieved 30 November 2012.
  27. ^ Brandl, Bernhard R. (2008). McLean, Ian S; Casali, Mark M (eds.). "METIS: the mid-infrared E-ELT imager and spectrograph". Proceedings of the SPIE. Ground-based and Airborne Instrumentation for Astronomy II. 7014: 70141N–70141N–15. Bibcode:2008SPIE.7014E..55B. doi:10.1117/12.789241. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  28. ^ "MICADO – Multi-AO Imaging Camera for Deep Observations". MICADO team. Retrieved 30 November 2012.
  29. ^ Davies, Richard (2010). McLean, Ian S; Ramsay, Suzanne K; Takami, Hideki (eds.). "MICADO: the E-ELT adaptive optics imaging camera". Proceedings of the SPIE. Ground-based and Airborne Instrumentation for Astronomy III. 7735: 77352A–77352A–12. arXiv:1005.5009. Bibcode:2010SPIE.7735E..77D. doi:10.1117/12.856379. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  30. ^ "E-ELT Optical Multi Object Spectrograph". OPTIMOS Consortium. Retrieved 30 November 2012.
  31. ^ "SIMPLE - A high resolution near-IR spectrograph for the E-ELT". SIMPLE Consortium. Retrieved 30 November 2012.
  32. ^ Oliva, E. (2008). McLean, Ian S; Casali, Mark M (eds.). "High-resolution near-IR spectroscopy: from 4m to 40m class telescopes" (PDF). Proceedings of the SPIE. Ground-based and Airborne Instrumentation for Astronomy II. 7014: 70141O–70141O–7. Bibcode:2008SPIE.7014E..56O. doi:10.1117/12.788821. Retrieved 30 November 2012. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  33. ^ "GMT Overview -- Giant Magellan Telescope". Retrieved 2011-06-15.
  34. ^ "About TMT -- Thirty Meter Telescope". Retrieved 2011-06-15.
  35. ^ "Artist's impression of the E-ELT and the starry night sky". ESO Press Release. Retrieved 13 February 2013.
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