ESO: Extremes Superfernrohr mit 42 m Durchmesser geplant

"At the end of the three year Final Design Study, we will know exactly how everything is going to be built including a detailed costing," said Cesarsky (ESO chief). "We then hope to start construction and have it ready by 2017, when we can install instruments and use it!"

The present concept, estimated to cost around 800 million euro, features as a baseline a telescope with a 42-m diameter mirror, and is revolutionary.

"A telescope of this size could not be built without a complete rethinking of the way we make telescopes," said Catherine Cesarsky.

The primary 42-m diameter mirror is composed of 906 hexagonal segments, each 1.45 m in size, while the secondary mirror is as large as 6 m in diameter. In order to overcome the fuzziness of stellar images due to atmospheric turbulence the telescope needs to incorporate adaptive mirrors into its optics [2]. A tertiary mirror, 4.2 m in diameter, relays the light to the adaptive optics system, composed of two mirrors: a 2.5-m mirror supported by 5000 or more actuators able to distort its own shape a thousand times per second, and one 2.7 m in diameter that allows for the final image corrections. This five mirror approach results in an exceptional image quality, with no significant aberrations in the field of view.

The site of the E-ELT is not yet fixed as studies are still undergoing with a plan to make a decision by 2008.

Extremely Large Telescopes are considered worldwide as one of the highest priorities in ground-based astronomy. They will vastly advance astrophysical knowledge, allowing detailed studies of subjects including planets around other stars, the first objects in the Universe, super-massive black holes, and the nature and distribution of the dark matter and dark energy which dominate the Universe.

With a diameter of 42 m and its adaptive optics concept, the E-ELT will be more than one hundred times more sensitive than the present-day largest optical telescopes, such as the 10-m Keck telescopes or the 8.2-m VLT telescopes.

"This is really the beginning of a new era for optical and infrared astronomy," said Catherine Cesarsky.

(ESO Press Release)