The European Extremely Large Telescope (ELT) is an astronomical observatory and the world’s largest optical/near-infrared extremely large telescope now under construction. Part of the European Southern Observatory (ESO), it is located on top of Cerro Armazones in the Atacama Desert of northern Chile. The design comprises a reflecting telescope with a 39.3-metre-diameter (126 foot) segmented primary mirror and a 4.2-metre-diameter secondary mirror, and will be supported by adaptive optics, six laser guide star units and multiple large science instruments.
Dubbed E-ELT for European Extremely Large Telescope, this revolutionary new ground-based telescope concept will have a 39-metre main mirror and will be the largest optical/near-infrared telescope in the world: “the world’s biggest eye on the sky”.
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The E-ELT has a main mirror 39 metres in diameter, covering a field on the sky about a tenth the size of the full Moon. The mirror design itself is revolutionary and is based on a novel five-mirror scheme that results in an exceptional image quality. The primary mirror consists of 798 segments, each 1.4 metres wide, but only 50 mm thick. The optical design calls for an immense secondary mirror four metres in diameter, bigger than the primary mirrors of any of ESO’s telescopes at La Silla.
Contracts for the manufacture of several of these challenging telescope components have just been signed by ESO’s Director General, Tim de Zeeuw, and representatives of three industrial contractors in the ESO Member States.
Introducing the ceremony, Tim de Zeeuw said: “It gives me great pleasure to sign these four contracts today, each for advanced components at the heart of the ELT’s revolutionary optical system. They underline how the construction of this giant telescope is moving ahead at full speed — on target for first light in 2024. We at ESO look forward to working with SCHOTT, SENER and FAMES — three leading industrial partners from our Member States.”
Adaptive mirrors are incorporated into the optics of the telescope to compensate for the fuzziness in the stellar images introduced by atmospheric turbulence. One of these mirrors is supported by more than 5000 actuators that can distort its shape a thousand times per second.The telescope will have several science instruments. It will be possible to switch from one instrument to another within minutes. The telescope and dome will also be able to change positions on the sky and start a new observation in a very short time.
The ability to observe over a wide range of wavelengths from the optical to mid-infrared will allow scientists to exploit the telescope’s size to the fullest extent.
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. ESO provides state-of-the-art research facilities to astronomers and is supported by Austria, Belgium, Brazil, the Czech Republic, Denmark, Finland, France, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. Several other countries have expressed an interest in membership.
On the 18th January,2017 ESO made a press release regarding the contract sighning, this is the press release;At a ceremony today at ESO’s Headquarters four contracts were signed for major components of the Extremely Large Telescope (ELT) that ESO is building. These were for: the casting of the telescope’s giant secondary and tertiary mirrors, awarded to SCHOTT; the supply of mirror cells to support these two mirrors, awarded to the SENER Group; and the supply of the edge sensors that form a vital part of the ELT’s huge segmented primary mirror control system, awarded to the FAMES consortium. The secondary mirror will be largest ever employed on a telescope and the largest convex mirror ever produced.
The construction of the 39-metre ELT, the largest optical/near-infrared telescope in the world, is moving forward. The giant telescope employs a complex five-mirror optical system that has never been used before and requires optical and mechanical elements that stretch modern technology to its limits.
The observatory aims to gather 13 times more light than the largest optical telescopes existing in 2014, and be able to correct for atmospheric distortions. It has around 256 times the light gathering area of the Hubble Space Telescope and, according to the E-ELT’s specifications, would provide images 16 times sharper than those from Hubble.
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.
The E-ELT is breaking the distance between earth and space, this project holds a great percentage in global space technology.The E-ELT programme was approved in 2012 and green light for construction was given at the end of 2014. First light is targeted for 2024.