On Saturday 15 October, the European Southern Observatory (ESO) opened the doors of its headquarters in Garching bei München, Bavaria, Germany, to the public. Throughout the day, thousands of visitors had the chance to help build a full-size mock-up mirror of the largest planned telescope in the world — the European Extremely Large Telescope (E-ELT) — and to experience many other aspects of ESO’s work.
Around 3100 people came to ESO’s headquarters on Saturday, curious to find out more about ESO’s world-class facilities and front-line scientific results. Visitors to the ESO Open House Day 2011 had a wide variety of activities to choose from. The highlight was to take part in the construction of a mock-up mirror for the European Extremely Large Telescope (E-ELT), giving participants a unique chance to experience the true scale of the world’s biggest eye on the sky. Enthusiastic visitors queued up to put the 798 cardboard hexagons in place, each measuring around 1.4 metres across. Using pegs and an outline of the mirror on the ground, visitors placed the hexagons on the ground to slowly form the giant mirror. Meanwhile, a time-lapse video of the assembly was filmed from the roof of the ESO building. When finished, the full-size mock-up measured 39.3 metres across and occupied an area of nearly 1000 square metres next to ESO Headquarters.
http://www.eso.org/public/news/eso1140/