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    OBSERVATORY SCIENCES
    SOFTWARE STUDY FOR EUROPEAN EXTREMELY LARGE TELESCOPE (E-ELT)

Software Study for European Extremely Large Telescope (E-ELT)

Observatory Sciences has undertaken a study, under contract to the European Southern Observatory, to review software options for the controls of the European Extremely Large Telescope (E-ELT). ESO gave the green light at the beginning of 2007 to proceed with detailed design studies for this giant telescope that has the potential to revolutionise ground-based astronomy. The E-ELT will be the world's largest optical/infrared telescope, with a primary mirror diameter of 42 metres, based on a design using new concepts specially developed for a telescope of this size. Construction is planned to start in 2010 with a budget of 850 million Euros, with the telescope completed and ready for use in 2017. Heralding a new era for optical and infrared astronomy, the E-ELT will deliver unprecedented acuity and light gathering power to provide unique images of objects at all scales, from those in our own solar system to exo-planetary systems and the very first points of light in our universe. Combined with its vast size, a key feature of the E-ELT will be its adaptive optics (AO) concepts, making it one hundred times more sensitive than the current largest optical telescopes, such as the 10m Keck telescopes or the 8.2m VLT telescopes. Previously, post focal adaptive optics have been built into the instruments rather than as an integral part of the telescope design itself. The E-ELT breaks the mould by embedding AO into the telescope as a baseline option. The primary 42m diameter mirror will be comprised of 984 hexagonal segments, each 1.2m in size, while the secondary mirror will be 6m in diameter. The incorporation of adaptive mirrors into the optics will be key in the imaging of distant objects. A tertiary mirror, 4.2m in diameter, will relay the light to the adaptive optics system, composed of two mirrors: a 2.5m mirror supported by some 5000 actuators able to distort its own shape a thousand times per second, and one 2.7m in diameter that allows for the final image corrections. The scale of the E-ELT project and complexity of the control requirements makes the choice of software framework critical. "Both the VLT and ALMA software frameworks have proven themselves in use at the European Southern Observatory," says Observatory Sciences consultant Philip Taylor, "but other software solutions such as ATST software, LabVIEW, TANGO, EPICS, DDS and PVSS-2 are also options we are looking at. The final decision will be based not only on the technical and managerial challenges provided by the E-ELT, but also on the basis of delivering software that will have both a long working life and easy upgradeability." The E-ELT could be on-stream as early as 2017, and is expected to be in operation until at least 2048. The site where the giant telescope will be built will be decided in 2008 following a world-wide review of potential observing sites.

Software for Astronomy and Physics Projects