Extremely large telescope

From Wikipedia, the free encyclopedia
(Redirected from Extremely Large Telescopes)
Jump to navigation Jump to search

Template:Short description Script error: No such module "For". Template:Comparison optical telescope primary mirrors.svg

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 Script error: No such module "convert". aperture fixed focus radio telescope of the Arecibo Observatory (now defunct). Freely steerable radio telescopes with diameters up to Script error: No such module "convert". have been in operation since the 1970s.

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

# Image Name Aperture (m) Area (m2) Primary mirror Altitude (m) First
light 		Notes Refs
1 File:Latest Rendering of the E-ELT.jpg Extremely Large Telescope
(ELT) 		39.3 978 798 × 1.45 m
hexagonal <templatestyles src="F//styles.css" />f/1 		3060 2029 Under construction at Cerro Armazones Obs., Chile [6][7][8]
2 File:Top view of tmt complex.jpg Thirty Meter Telescope
(TMT) 		30.0 655 492 × 1.45 m
hexagonal <templatestyles src="F//styles.css" />f/1 		4050 Un­known Construction approved at Mauna Kea Obs. in Hawaii, USA, halted as of September 2019 due to protests [4][9][10][11]
3 File:Giant Magellan Telescope - artist's concept.jpg Giant Magellan Telescope
(GMT) 		24.5 368 7 × 8.4 m
circular <templatestyles src="F//styles.css" />f/0.71 		2516 2030s Under construction at Las Campanas Obs., Chile;
6/7 mirrors cast 		[5][12][13]
4 File:LBT 2.png Large Binocular Telescope
(LBT) 		11.8
(equiv. area)
22.8
(equiv. detail limit) 		111 2 × 8.4 m
circular 		3221 2008 Largest 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 relation cost ∝ D2.7Script error: No such module "Check for unknown parameters"..[15]

Name Cost
(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

European Extremely Large Telescope (39.2m), Chile Thirty Meter Telescope (30m), Hawaii
Giant Magellan Telescope (24.5m), Chile Large Binocular Telescope (2x 8.4m, 11.8m)Keck Observatory (2x10m), Hawaii
Very Large Telescope (4x 8.2m, VLTI)Gran Telescopio Canarias (10.4m)
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

References

<templatestyles src="Reflist/styles.css" />

  1. ↑ As A Skeleton Science Case For Extremely Large (20m–100m) Ground-based Telescopes (ELTs) and first section of ELT Roadmap Script error: No such module "webarchive"., PDF
  2. ↑ Script error: No such module "citation/CS1".
  3. ↑ Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "Citation/CS1".
  5. ↑ a b Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ Script error: No such module "citation/CS1".
  9. ↑ Script error: No such module "citation/CS1".
  10. ↑ TMT Timeline, accessed February 11, 2018
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ a b Script error: No such module "citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".
  19. ↑ Script error: No such module "citation/CS1".
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "citation/CS1".
  23. ↑ Script error: No such module "citation/CS1".
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ Script error: No such module "citation/CS1".
  26. ↑ Script error: No such module "citation/CS1".
  27. ↑ https://home.ifa.hawaii.edu/users/kuhn/tmp.html%25%7Ctitle= 22 March 2002.
  28. ↑ http://optik2.mtk.nao.ac.jp/futureplan/eltproje.htmScript error: No such module "Unsubst".
  29. ↑ Script error: No such module "citation/CS1".
  30. ↑ Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".

External links

Template:Portal bar Template:Astronomy navbox

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Extremely_large_telescope&oldid=3929919"