VDL and TNO deliver prototypes for the world’s largest telescope

On 15 July, VDL and TNO have delivered three prototypes to the European Southern Observatory (ESO) to support the main mirror of what will be the largest telescope in the world. This telescope, the European Extremely Large Telescope (E-ELT), is intended to surpass all existing telescopes. With the E-ELT the ESO hopes to obtain more information about the formation of the Milky Way galaxy, stars and dark matter. ESO want to build this telescope in the Chilean Atacama Desert at an elevation of 3060 metres. The plan calls for completion of the telescope in 2018.

Telescope
The main mirror of the telescope will comprise of nearly 1000 hexagonal mirror segments, each positioned with nanometer accuracy, that will work together to form a 42 meter parabolic whole. Each mirror segment is supported by a frame. The first prototypes for this frame are developed by TNO en manufactured by VDL ETG Projects.

Frame
The frame consists of a stiff interface to carry the load of the mirror of about 1,4 meters in width and 50 mm thick, and motors to compensate for figure errors due to gravity and environmental disturbances. Each mirror segment is supported by 27 struts mounted on the whiffletree and 3 position actuators used to tip tilt the segment. Special about the prototype of TNO and VDL is its low mass, high stiffness, uncoupled axial and lateral whiffletree support and lack of friction. All this combined with cost effectiveness. By combining such a huge mirror with such pinpoint precision, scientists expect spectacular results.

Decision
By the end of December 2010 VDL and TNO hope to secure approval by ESO for the full development of the frames. When ESO chooses the prototypes of TNO and VDL it will be a project worth several millions of euros. The construction phase is planned to start in 2011.


   

More information:
TNO - TNO and VDL deliver high-tech mirror support proto-types for the largest telescope ever made
ESO - European Southern Observatory


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