From ESO: “Contract Signed for Final Design and Construction of Largest Adaptive Mirror Unit in the World”
19 June 2015
ESO, Adaptive Optics Department (Instrumentation)
Garching bei München, Germany
Tel: +49 89 320 06 322
Fax: +49 89 320 2362
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
ESO has signed a contract with the AdOptica consortium in Italy — ADS International and Microgate, partnered with INAF (Istituto Nazionale di Astrofisica) as subcontractors — for the final design and construction of the very challenging adaptive unit for the fourth mirror (M4) of the European Extremely Large Telescope (E-ELT). This mirror system will surpass any adaptive mirror ever made for a telescope and be the largest of its kind.
The contract was signed by representatives of AdOptica and ESO at a ceremony at ESO Headquarters on 19 June 2015.
The AdOptica contract does not include the manufacture of the shell mirrors themselves. These will be constructed under a separate contract that will be announced soon.
The M4 deformable 2.4-metre mirror system forms a fundamental part of the E-ELT. It consists of a mirror made from six component petals, actuators and control systems that can correct the image distortion caused by the turbulence of the Earth’s atmosphere in real time, as well as correct for deformations of the structure of the main telescope caused by wind. The corrected optical system will make the images obtained at the telescope almost as sharp as those taken in space .
Construction of a mirror system like this has never been attempted before and studies began in 2008 with two competitive contracts for a preliminary design for the E-ELT. In 2012, AdOptica was selected from two competitive designs. Since 2012, AdOptica has developed the preliminary design for the unit. The design has evolved significantly to fulfil stability requirements. The preliminary design review was successfully passed in April 2015 and the company has demonstrated the design with a one-metre mirror demonstration prototype that fulfils ESO’s performance requirements.
The new contract will be for the final design and manufacturing of the M4 unit. The planning calls for the final design to be completed by mid-2017, and then the unit will be manufactured and tested in Europe against the performance requirements before being shipped to Chile by the end of 2022.
 The mirror’s shape is controlled by approximately 5700 actuators. A hexapod allows tip/tilt and large lateral movements.
See the full article here.
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ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.