Facts | ELT

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/>Southern<br />Observatory</p> </div> <div class="position-absolute big-header-title big-header-title-facts" > <span style="color: rgb(232, 133, 38);">About</span> | Facts about the ELT </div> </div> <nav id="main-navbar" class="d-none d-lg-flex navbar sticky-top_ navbar-dark navbar-expand-lg mysticky py-2_ py-xl-0" style="background-color: #000000;"> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggler" aria-controls="navbarToggler" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse justify-content-around" id="navbarToggler"> <ul class="navbar-nav mx-auto mt-0"> <li class="nav-home nav-item menu-item d-flex align-items-center text-center"> <a class="nav-link" href="/">ELT HOME</a> </li> <li class="nav-about nav-item dropdown dropdown-menu-top menu-item d-flex align-items-center text-center"> <a class="nav-link dropdown-toggle_" 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href="/science/exoplanets/">Exoplanets</a> <a class="nav-science-stars dropdown-item" href="/science/stars/">Stars</a> <a class="nav-science-blackholes dropdown-item" href="/science/blackholes/">Black Holes</a> <a class="nav-science-galaxies dropdown-item" href="/science/galaxies/">Galaxies</a> <a class="nav-science-cosmodm dropdown-item" href="/science/cosmodm/">Cosmology and Dark Matter</a> <a class="nav-science-fundamentalphysics dropdown-item" href="/science/fundamentalphysics/">Fundamental Physics</a> <a class="nav-science-discoveries dropdown-item" href="/science/discoveries/">Unexpected Discoveries</a> </div> </li> <li class="nav-multimedia nav-item menu-item d-flex align-items-center text-center"> <a class="nav-link" href="/media/">NEWS & MULTIMEDIA</a> </li> <li class="nav-success nav-item menu-item d-flex align-items-center text-center"> <a class="nav-link" href="/success/buildingon/">SUCCESS STORIES</a> </li>           </ul> </div> </nav> <div class="container-fluid container-darkblue"> <div class="w-100 d-flex flex-column align-items-center justify-content-around"> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Name</div> <div class="mx-auto fact-value text-center" style="" data-id="1"> <p>Extremely Large Telescope (ELT)</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Main mirror diameter</div> <div class="mx-auto fact-value text-center" style="" data-id="7"> <p>39 metres</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Light collecting area</div> <div class="mx-auto fact-value text-center" style="" data-id="14"> <p>978 square metres</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Number of main mirror segments</div> <div class="mx-auto fact-value text-center" style="" data-id="15"> <p>798</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Alignment precision of the different segments that make up the main mirror</div> <div class="mx-auto fact-value text-center" style="" data-id="29"> <p>Tens of nanometres (10000 thinner than a human hair) across its entire 39-metre diameter</p> <p> </p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Number of edge sensors that will measure the relative positions of the segments</div> <div class="mx-auto fact-value text-center" style="" data-id="26"> <p>4608</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Amount of glass-ceramic Zerodur(c) in the telescope mirrors</div> <div class="mx-auto fact-value text-center" style="" data-id="27"> <p>140 tonnes, of which 132 tonnes in the primary mirror alone</p> </div> </div> </div> <div class="container-fluid container-darkblue"> <div class="container-paragraph facts-title" style="">How much light will the ELT gather?</div> <div class="swiper-container swiper-container-carousel"> <div class="h-100_ w-100_ swiper-wrapper"> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts1.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts2.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts3.jpg" /> </div> </div> <div class="swiper-button-next swiper-button-white swiper-button-next-carousel"></div> <div class="swiper-button-prev swiper-button-white swiper-button-prev-carousel"></div> </div> </div> <div class="container-fluid container-darkblue"> <div class="w-100 d-flex flex-column align-items-center justify-content-around"> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Type</div> <div class="mx-auto fact-value text-center" style="" data-id="5"> <p>Optical/near-infrared extremely large telescope</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Optical Design</div> <div class="mx-auto fact-value text-center" style="" data-id="6"> <p>Five-mirror design</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Telescope field of view</div> <div class="mx-auto fact-value text-center" style="" data-id="16"> <p>10 arcminutes</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Enclosure</div> <div class="mx-auto fact-value text-center" style="" data-id="4"> <p>Hemispherical Dome</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Time needed to walk from the entrance of the dome to the top via the set of stairs and walkways fixed to the inner side of the dome</div> <div class="mx-auto fact-value text-center" style="" data-id="17"> <p>~30 minutes</p> </div> </div> </div> <div class="container-fluid container-darkblue"> <div class="swiper-container swiper-container-carousel2"> <div class="h-100_ w-100_ swiper-wrapper"> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: rgb(28, 57, 98);"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts4.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: rgb(11, 26, 41);"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts5.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts6.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts7.jpg" /> </div> <div class="swiper-slide d-flex align-items-center justify-content-center" style="background-color: ;"> <img class="h-100 w-100" src="https://cdn.eso.org/images/wallpaper2/about-facts8.jpg" /> </div> </div> <div class="swiper-button-next swiper-button-white swiper-button-next-carousel2"></div> <div class="swiper-button-prev swiper-button-white swiper-button-prev-carousel2"></div> </div> </div> <div class="container-fluid container-darkblue"> <div class="w-100 d-flex flex-column align-items-center justify-content-around"> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Site</div> <div class="mx-auto fact-value text-center" style="" data-id="2"> <p>Cerro Armazones, Atacama Desert, Chile</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Altitude</div> <div class="mx-auto fact-value text-center" style="" data-id="3"> <p>3046 m</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Height of rock removed from the top of Armazones to create the platform for the ELT</div> <div class="mx-auto fact-value text-center" style="" data-id="18"> <p>~18 metres</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Amount of rock removed to make room for the 150 metre by 300 metre ELT platform</div> <div class="mx-auto fact-value text-center" style="" data-id="19"> <p>~220 000 m<sup>3</sup></p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Distance between Armazones and Paranal (by air)</div> <div class="mx-auto fact-value text-center" style="" data-id="20"> <p>23 km</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Planned duration of the telescope construction</div> <div class="mx-auto fact-value text-center" style="" data-id="28"> <p>About 12 years</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Planned year of technical first light</div> <div class="mx-auto fact-value text-center" style="" data-id="21"> <p>2028</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Estimated lifespan</div> <div class="mx-auto fact-value text-center" style="" data-id="22"> <p>30+ years</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Budget</div> <div class="mx-auto fact-value text-center" style="" data-id="23"> <p>€1.45 billion</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Number of industrial contracts above €500 000 made to date</div> <div class="mx-auto fact-value text-center" style="" data-id="24"> <p>53</p> </div> <div class="fact-name mx-auto text-center" style="color: #ff8c00;">Number of ESO staff (Full-Time Equivalent) the ELT uses on average during 2018–2022</div> <div class="mx-auto fact-value text-center" style="" data-id="25"> <p>~100 each year</p> </div> </div> </div> <footer class="container-fluid container-footer"> <div class="row d-flex align-items-center justify-content-between w-100"> <div class="col-12 col-lg-3 pb-3 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