Europe's Extremely Large Telescope on Its Way

Today, the council of the European Southern Observatory (ESO) fired the starting gun for the construction of what will be, by a big margin, the largest optical-infrared telescope ever built. The €1.1 billion behemoth, with the appropriately superlative name the European Extremely Large Telescope (E-ELT), will have a main mirror 39.2 meters across, dwarfing the 11.9-meter effective size of today's largest telescope, the Large Binocular Telescope.

Today's green-light for initial construction is not a full approval for the project, because some of ESO's 15 member states have not yet secured the needed additional funding. But the approval does allow work to begin on building roads to the telescope site at Cerro Armazones in the Atacama Desert of northern Chile and on development of the instrument's adaptive optics.

"The E-ELT is starting to become reality," ESO Director General Tim de Zeeuw said in a statement. "However, with a project of this size it is expected that approval of the extra expenditure will take time. Council at the same time recognises that preparatory work must start now in order for the project to be ready for a full start of construction in 2012."

Although two rival telescope efforts in the United States—the Giant Magellan Telescope and the Thirty Meter Telescope—are struggling to secure funding from the cash-strapped National Science Foundation, ESO has been pushing ahead with a schedule that will see construction begin in 2012 and observations start in 2022. Chile has already donated the necessary land at Armazones, and some states, such as the United Kingdom, are pitching in for instruments. Member states' annual contributions to ESO, plus contributions from new member Brazil, are expected to raise two-thirds of the funds needed to complete the E-ELT. To make up the remaining one-third, ESO is asking members to up their contributions by 2%. The Czech Republic, Sweden, and Finland have already agreed to chip in the extra funds, but the other members have asked for more time, hence today's partial approval. Full approval of the project is expected by mid-2012.