The European Extremely Large Telescope (E-ELT), is a revolutionary new ground-based telescope concept with a 39 meters primary mirror.

The adaptive optics is mainly based on two corrective surfaces, a tilting mirror (M5) and a high-order adaptive mirror (M4).

In late 2007 ESO granted two competitive Preliminary Design Studies of the M4 adaptive unit, one of the most critical and complex parts of the telescope. One contract has been assigned to Microgate (acting as Prime Contractor) in team with ADS, SAFRAN/SAGEM and INAF.

In 2012 the AdOptica consortium, made by Microgate and ADS, obtained an advanced preliminary design study aimed to consolidate the previous study while adapting to the evolution of the telescope design.

The adaptive unit is a 2.4 x 2.5m elliptic mirror controlled by 5316 contactless actuators.

Our design exploits the concept adopted in all previous units, but several implementation details were changed to deal with the challenges imposed by the size of the M4 unit.

In particular we adopted a modular concept based on replaceable control bricks that allows easy interfacing and system maintainability. Differently to the previous systems, the mechanical support structure acts also as reference for controlling the optical surfaces.

The baseline concept adopts a flat segmented thin shell made of six identical petals.

Microgate tasks cover control system design and simulation, electronic design, electronic manufacturing and test of Demonstration Prototype.

Rendering by ADS International & ESO

Sample rendering of the E-ELT M4 brick