|
The European Extremely Large Telescope (E-ELT) is a ground-based extremely large telescope for the optical/near-infrared range, currently being built by the European Southern Observatory (ESO) on top of Cerro Armazones in the Atacama Desert of northern Chile. The design comprises a reflecting telescope with a 39.3-metre-diameter segmented primary mirror, a 4.2-metre-diameter secondary mirror, and will be supported by adaptive optics and multiple instruments.〔 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 protoplanetary disks around stars in the making.〔 On 11 June 2012, the ESO Council approved the E-ELT programme's plans to begin civil works at the telescope site, with the construction of the telescope itself pending final agreement with the governments of some member states.〔 Construction work on the E-ELT site started in June 2014.〔 In December 2014 ESO had secured over 90% funding and authorized to start construction of the telescope, which will cost around one billion euros for the first construction phase.〔 First light is planned for 2024.〔 == History == On 26 April 2010, the European Southern Observatory (ESO) Council selected Cerro Armazones, Chile, as the baseline site for the planned E-ELT.〔 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.〔 Early designs included a segmented primary 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. It reduced projected costs from 1.275 billion to 1.055 billion euros and should allow the telescope to be finished sooner. The smaller secondary is a particularly important change; 4.2 m places it within the capabilities of multiple manufacturers, and the lighter mirror unit avoids the need for high-strength materials in the secondary mirror support spider.〔 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." The ESO Council endorsed the revised baseline design in June 2011 and expected a construction proposal for approval in December 2011.〔 Funding was subsequently included in the 2012 budget for initial work to begin in early 2012.〔(【引用サイトリンク】title=The E-ELT Moves Closer to Reality )〕 The project received preliminary approval in June 2012.〔 ESO approved the start of construction in December 2014, with over 90% funding secured.〔 The design phase of the 5-mirror anastigmat was 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 42 m to 39.3 m), the construction cost is estimated to be €1.055 billion (including first generation instruments).〔(【引用サイトリンク】url=http://www.eso.org/public/teles-instr/e-elt/e-elt_rev.html )〕 The start of operations is planned for 2024.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「European Extremely Large Telescope」の詳細全文を読む スポンサード リンク
|