Extremely large telescope

Last updated
Comparison of nominal sizes of apertures of the above extremely large telescopes and some notable optical telescopes Comparison optical telescope primary mirrors.svg
Comparison of nominal sizes of apertures of the above extremely large telescopes and some notable optical telescopes

An extremely large telescope (ELT) is an astronomical observatory featuring an optical telescope with an aperture for its primary mirror from 20 metres up to 100 metres across, [1] [2] when discussing reflecting telescopes of optical wavelengths including ultraviolet (UV), visible, and near infrared wavelengths. Among many planned capabilities, extremely large telescopes are planned to increase the chance of finding Earth-like planets around other stars. [3] Telescopes for radio wavelengths can be much bigger physically, such as the 300 metres (330 yards) aperture fixed focus radio telescope of the Arecibo Observatory (now defunct). Freely steerable radio telescopes with diameters up to 100 metres (110 yards) have been in operation since the 1970s.

Contents

These telescopes have a number of features in common, in particular the use of a segmented primary mirror (similar to the existing Keck telescopes), and the use of high-order adaptive optics systems. [4] [5]

Although extremely large telescope designs are large, they can have smaller apertures than the aperture synthesis on many large optical interferometers. However, they may collect much more light, along with other advantages.

List of telescopes

#ImageNameAperture (m)Area (m2)Primary mirrorAltitude (m)First
light		NotesRefs
1 Latest Rendering of the E-ELT.jpg Extremely Large Telescope
(ELT)		39.3978798 × 1.45 m
hexagonal f/1		30602028Under construction at Cerro Armazones Obs., Chile [6] [7] [8]
2 Top view of tmt complex.jpg Thirty Meter Telescope
(TMT)		30.0655492 × 1.45 m
hexagonal f/1		40502030sConstruction approved at Mauna Kea Obs. in Hawaii, USA, halted as of September 2019 due to protests [4] [9] [10] [11]
3 Giant Magellan Telescope - artist's concept.jpg Giant Magellan Telescope
(GMT)		24.53687 × 8.4 m
circular f/0.71		25162029Under construction at Las Campanas Obs., Chile;
6/7 mirrors cast		 [5] [12] [13]
4 LBT 2.png Large Binocular Telescope
(LBT)		11.8
(equiv. area)
22.8
(equiv. detail limit)		1112 × 8.4 m
circular		32212008Largest non-segmented mirrors.
Located on Mount Graham, Arizona, USA		 [14]
Note: Aperture of LBT: the baseline is obtained via aperture synthesis.

Budget

Possible budget figures, which are estimates and can vary over time. For construction costs, it is recommended to estimate the cost of a giant telescope with the following equation: [15]

NameCost
(est. USD)		Alternate
Extremely Large Telescope (ELT)$1590 million€1300 million [16]
Thirty Meter Telescope (TMT)$1400 million$3600 million [17]
Giant Magellan Telescope (GMT)$1000 million$2540 million [17]
Large Binocular Telescope (LBT)$120 million

Projects

Latest Rendering of the E-ELT.jpg   Top view of tmt complex.jpg
Giant Magellan Telescope - artist's concept.jpg LargeBinoTelescope NASA.jpg KeckTelescopes-hi.png
Paranal opendome.jpg Grantelescopio.jpg
Extremely large telescopes:

Compared to the LBT, Keck, VLT, and GTC

There were several telescopes in various stages in the 1990s and early 2000s, and some developed into construction projects.

Under construction
Funded construction
Projects

Some of these projects have been cancelled, or merged into ongoing extremely large telescopes.

See also

Related Research Articles

<span class="mw-page-title-main">Very Large Telescope</span> Telescope in the Atacama Desert, Chile

The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with a primary mirror that measures 8.2 meters in diameter. These optical telescopes, named Antu, Kueyen, Melipal, and Yepun, are generally used separately but can be combined to achieve a very high angular resolution. The VLT array is also complemented by four movable Auxiliary Telescopes (ATs) with 1.8-meter apertures.

<span class="mw-page-title-main">Overwhelmingly Large Telescope</span> Proposed extremely large telescope

The Overwhelmingly Large Telescope (OWL) was a conceptual design by the European Southern Observatory (ESO) organization for an extremely large telescope, which was intended to have a single aperture of 100 meters in diameter. Because of the complexity and cost of building a telescope of this unprecedented size, ESO has decided to focus on the 39-meter diameter Extremely Large Telescope instead.

<span class="mw-page-title-main">European Southern Observatory</span> Intergovernmental organization and observatory in Chile

The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based astronomy. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and access to the southern sky. The organisation employs over 750 staff members and receives annual member state contributions of approximately €162 million. Its observatories are located in northern Chile.

<span class="mw-page-title-main">Large Binocular Telescope</span> Telescope for optical astronomy

The Large Binocular Telescope (LBT) is an optical telescope for astronomy located on 10,700-foot (3,300 m) Mount Graham, in the Pinaleno Mountains of southeastern Arizona, United States. It is a part of the Mount Graham International Observatory.

<span class="mw-page-title-main">W. M. Keck Observatory</span> Astronomical observatory in Hawaii

The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have 10 m (33 ft) aperture primary mirrors, and, when completed in 1993 and 1996, they were the largest optical reflecting telescopes in the world. They have been the third and fourth largest since 2006.

<span class="mw-page-title-main">Active optics</span> Shaping technology for reflecting telescopes

Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, and mechanical stress. Without active optics, the construction of 8 metre class telescopes is not possible, nor would telescopes with segmented mirrors be feasible.

<span class="mw-page-title-main">Steward Observatory</span> Observatory in Tucson, Arizona (US)

Steward Observatory is the research arm of the Department of Astronomy at the University of Arizona (UArizona). Its offices are located on the UArizona campus in Tucson, Arizona (US). Established in 1916, the first telescope and building were formally dedicated on April 23, 1923. It operates, or is a partner in telescopes at five mountain-top locations in Arizona, one in New Mexico, one in Hawaii, and one in Chile. It has provided instruments for three different space telescopes and numerous terrestrial ones. Steward has one of the few facilities in the world that can cast and figure the very large primary mirrors used in telescopes built in the early 21st century.

<span class="mw-page-title-main">National Optical Astronomy Observatory</span> United States national observatory

The National Optical Astronomy Observatory (NOAO) was the United States national observatory for ground-based nighttime ultraviolet-optical-infrared (OUVIR) astronomy. The National Science Foundation (NSF) funded NOAO to provide forefront astronomical research facilities for US astronomers. Professional astronomers from any country in the world could apply to use the telescopes operated by NOAO under the NSF's "open skies" policy.

<span class="mw-page-title-main">Magellan Telescopes</span> Optical telescopes located at Las Campanas Observatory in Chile

The Magellan Telescopes are a pair of 6.5-metre-diameter (21 ft) optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T. Clay. First light for the telescopes was on September 15, 2000 for the Baade, and September 7, 2002 for the Clay. A consortium consisting of the Carnegie Institution for Science, University of Arizona, Harvard University, the University of Michigan and the Massachusetts Institute of Technology built and operate the twin telescopes. The telescopes were named after the sixteenth-century Portuguese explorer Ferdinand Magellan.

<span class="mw-page-title-main">Paranal Observatory</span> Astronomical observatory in Chile

Paranal Observatory is an astronomical observatory operated by the European Southern Observatory (ESO). It is located in the Atacama Desert of Northern Chile on Cerro Paranal at 2,635 m (8,645 ft) altitude, 120 km (70 mi) south of Antofagasta. By total light-collecting area, it is the largest optical-infrared observatory in the Southern Hemisphere; worldwide, it is second to the Mauna Kea Observatory on Hawaii.

<span class="mw-page-title-main">Giant Magellan Telescope</span> Telescope under construction in Chile

The Giant Magellan Telescope (GMT) is a ground-based, extremely large telescope currently under construction at Las Campanas Observatory in Chile's Atacama Desert. With a primary mirror diameter of 25.4 meters, it is expected to be the largest Gregorian telescope ever built, observing in optical and mid-infrared wavelengths. Commissioning of the telescope is anticipated in the early 2030s.

<span class="mw-page-title-main">Extremely Large Telescope</span> Major astronomical facility in Chile

The Extremely Large Telescope (ELT) is an astronomical observatory under construction. When completed, it will be the world's largest optical and near-infrared extremely large telescope. Part of the European Southern Observatory (ESO) agency, it is located on top of Cerro Armazones in the Atacama Desert of northern Chile.

<span class="mw-page-title-main">Las Campanas Observatory</span> Observatory

Las Campanas Observatory (LCO) is an astronomical observatory managed by the Carnegie Institution for Science (CIS). Located in Chile's Atacama Region, it sits about 100 kilometres (62 mi) northeast of the city of La Serena. The LCO's telescopes and facilities are positioned near the northern end of a 7 km (4.3 mi) mountain ridge. Cerro Las Campanas, situated near the southern end of this ridge and standing over 2,500 m (8,200 ft) tall, will be the future site of the Giant Magellan Telescope.

<span class="mw-page-title-main">Thirty Meter Telescope</span> Future observatory in the United States

The Thirty Meter Telescope (TMT) is a planned extremely large telescope (ELT) proposed to be built on Mauna Kea, on the island of Hawai'i. The TMT would become the largest visible-light telescope on Mauna Kea.

<span class="mw-page-title-main">Astronomical interferometer</span> Array used for astronomical observations

An astronomical interferometer or telescope array is a set of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, nebulas and galaxies by means of interferometry. The advantage of this technique is that it can theoretically produce images with the angular resolution of a huge telescope with an aperture equal to the separation, called baseline, between the component telescopes. The main drawback is that it does not collect as much light as the complete instrument's mirror. Thus it is mainly useful for fine resolution of more luminous astronomical objects, such as close binary stars. Another drawback is that the maximum angular size of a detectable emission source is limited by the minimum gap between detectors in the collector array.

<span class="mw-page-title-main">Segmented mirror</span> Array of smaller mirrors designed to act as one large curved mirror

A segmented mirror is an array of smaller mirrors designed to act as segments of a single large curved mirror. The segments can be either spherical or asymmetric. They are used as objectives for large reflecting telescopes. To function, all the mirror segments have to be polished to a precise shape and actively aligned by a computer-controlled active optics system using actuators built into the mirror support cell.

The California Extremely Large Telescope(CELT) was a proposal for an extremely large telescope design first proposed in the 1990s by a consortium of Californian Universities. The design was for a segmented 30 m diameter astronomical telescope. The CELT had a positive reception and continued to be developed, and was renamed the Thirty Meter Telescope (TMT) around 2003–4. The CELT was one of the earlier and more successful proposals for extremely large telescopes.

<span class="mw-page-title-main">Cerro Armazones</span> Mountain in Chile

Cerro Armazones is a mountain located in the Sierra Vicuña Mackenna of the Chilean Coast Range of the Andes, approximately 130 km (81 mi) southeast of Antofagasta in the Antofagasta Region, Chile. The mountain is situated in an ideal location for optical astronomy due to its 89% cloudless nights annually. On 26 April 2010, the European Southern Observatory Council selected Cerro Armazones as the site for the planned Extremely Large Telescope (ELT); construction commenced in June 2014. The first light observation is scheduled for 2027.

References

  1. ↑ As A Skeleton Science Case For Extremely Large (20m–100m) Ground-based Telescopes (ELTs) and first section of ELT Roadmap Archived 2015-05-18 at the Wayback Machine , PDF
  2. ↑ Overbye, Dennis (8 March 2024). "Good News and Bad News for Astronomers' Biggest Dream - The National Science Foundation takes a step (just one) toward an "extremely large telescope."". The New York Times . Archived from the original on 8 March 2024. Retrieved 8 March 2024.
  3. ↑ Jha, Alok (5 August 2006). "Extremely Large Telescope could reveal secrets of life, the universe and everything". The Guardian .
  4. 1 2 "Thirty Meter Telescope Construction Proposal" (PDF). TMT Observatory Corporation. 2007-09-12: 29. Archived from the original (PDF) on 2016-03-24. Retrieved 2009-07-24.{{cite journal}}: Cite journal requires |journal= (help)
  5. 1 2 "Chapter 6: Optics" (PDF). GMT Conceptual Design Report. GMT Consortium. pp. 6–3. Retrieved 2008-04-02.
  6. ↑ "Groundbreaking for the E-ELT". 19 June 2014.
  7. ↑ Schilling, Govert (14 June 2011). "Europe Downscales Monster Telescope to Save Money". Science Insider.
  8. ↑ "The E-ELT in numbers". Archived from the original on 2009-08-21. Retrieved 2009-08-11.
  9. ↑ Thirty Meter Telescope timeline page, TMT Observatory Project, archived from the original on 2010-09-25, retrieved 2010-10-12
  10. ↑ TMT Timeline, accessed February 11, 2018
  11. ↑ "Hawaii top court approves controversial Thirty Meter Telescope". BBC News. 31 October 2018.
  12. ↑ Howell, Elizabeth (29 December 2014). "Giant telescope gets $20m funding boost as design takes shape". Sen. Archived from the original on 17 July 2021. Retrieved 8 January 2015.
  13. ↑ "Giant Magellan Telescope – 6th mirror cast". 12 March 2021. Retrieved 11 July 2023.
  14. ↑ "Large Binocular Telescope Achieves First Binocular Light" (Press release). Large Binocular Telescope Corporation. 2008-02-28. Archived from the original on 2008-03-10.
  15. ↑ Stepp, Larry; Daggert, Larry; Gillett, Paul. "Estimating the costs of extremely large telescopes" (PDF). National Optical Astronomy Observatory.
  16. ↑ "Funding boost for ESO's Extremely Large Telescope". The European Southern Observatory (ESO). Retrieved 29 August 2024.
  17. 1 2 "NSF board approves funding for just one of two proposed giant telescopes". Science (Science.org). Retrieved 29 August 2024.
  18. ↑ "Elt | Eso".
  19. ↑ "Giant Magellan Telescope". Giant Magellan Telescope.
  20. ↑ "TMT International Observatory". TIO.
  21. ↑ "AURA NIO: Home". October 19, 2006. Archived from the original on 2006-10-19.
  22. ↑ "The ESO 100-m OWL optical telescope concept". www.eso.org.
  23. ↑ "VLOT } The Very Large Optical Telescope for CI am Canada". May 2, 2009. Archived from the original on 2009-05-02.
  24. ↑ "Atacama". Archived from the original on 2003-12-02. Retrieved 2006-12-13.
  25. ↑ "Euro50". December 14, 2006. Archived from the original on 2006-12-14.
  26. ↑ "LPT | Large Petal Telescope". November 23, 2006. Archived from the original on 2006-11-23.
  27. ↑ https://home.ifa.hawaii.edu/users/kuhn/tmp.html%25%7Ctitle= 22 March 2002.
  28. ↑ http://optik2.mtk.nao.ac.jp/futureplan/eltproje.htm%5B%5D
  29. ↑ "index.html". June 5, 2002. Archived from the original on 2002-06-05.
  30. ↑ "MAXAT – the Maximum Aperture Telescope". Archived from the original on 6 July 2007.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.