This image, taken in late June 2023, shows a night view of the construction site of ESO’s Extremely Large Telescope at Cerro Armazones, in Chile's Atacama Desert. Credit: ESO.
The European Southern Observatory continues to build the largest telescope in the world, the Extremely Large Telescope (ELT). Construction of the telescope began in 2014 with flattening the top of a mountain named Cerro Armazones in Chile’s Atacama Desert.
ESO just announced that progress on construction has crossed the 50% mark. The remaining work should take another five years. When it finally comes online in 2028, the telescope will have a 39-meter (128 ft) primary mirror of 798 hexagonal segments, making it the largest telescope in the world for visible and infrared light. The new telescope should help to answer some of the outstanding questions about our Universe, such as how the first stars and galaxies formed, and perhaps even be able to take direct images of extrasolar planets.
This artist’s rendering of the E-ELT is based on the detailed construction design for the telescope. Image: ESO/L. Calçada/ACe Consortium
We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.
In this series we’ll look at 6 of the world’s Super Telescopes:
The European Extremely Large Telescope (E-ELT) is an enormous ‘scope being built by the European Southern Observatory. It’s under construction right now in the high-altitude Atacama Desert of northern Chile. The ESO, with its partners, has built some of the largest and most technically advanced telescopes in the world, like the Atacama Large Millimeter Array (ALMA) and the Very Large Telescope (VLT.) But with a 39 meter primary mirror, the E-ELT will dwarf the other telescopes in the ESO’s fleet.
As Dr Michele Cirasuolo, Programme Scientist for the ELT told Universe Today, “The Extremely Large Telescope (ELT) is the flagship project of the European Southern Observatory (ESO), and when completed in 2024 will be the largest optical/infrared telescope in the world. It represents the next step forward and it will complement the research done with the GMT (Giant Magellan Telescope) and other large telescopes being built.”
This artist’s rendering of the E-ELT shows the 39 meter segmented mirror at the heart of the scope. ESO/L. Calçada/ACe Consortium
The E-ELT is the successor to the Overwhelmingly Large Telescope (OWL), which was the ESO backed away from due to its €1.5 billion price tag. Instead, the ESO focussed on the E-ELT. The site for the E-ELT was selected in 2010, and over the next couple years the design was finalized.
Like other telescopes—including the Keck Telescope—the E-ELT’s primary mirror will be made up of individually manufactured hexagonal segments; 798 of them. The primary mirror will be fitted with edge sensors to ensure that each segment of the mirror is corrected in relation to its neighbours as the scope is aimed or moved, or as it is disturbed by temperature changes, wind, or vibrations.
The E-ELT is actually a 5 mirror system. Along with the enormous primary mirror, and the secondary mirror, there are three other mirrors. An unusual aspect of the E-ELT’s design is its tertiary mirror. This tertiary mirror will give the E-ELT better image quality over a larger field of view than a primary and secondary mirror can.
The ‘scope also has two other mirrors which provide adaptive optics and image stabilization, as well as allowing more large science instruments to be mounted to the ‘scope simultaneously.
This diagram shows the novel 5-mirror optical system of ESO’s Extremely Large Telescope (ELT). Before reaching the science instruments the light is first reflected from the telescope’s giant concave 39-metre segmented primary mirror (M1), it then bounces off two further 4-metre-class mirrors, one convex (M2) and one concave (M3). The final two mirrors (M4 and M5) form a built-in adaptive optics system to allow extremely sharp images to be formed at the final focal plane. Image By ESO – https://www.eso.org/public/images/eso1704a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=55268266
The Science: What Will the E-ELT Study?
The E-ELT is designed for an ambitious science agenda. One of the most exciting aspects of the E-ELT is its potential to capture images of extra-solar planets. The 39 meter mirror will not only collect more light from distant, faint objects, but will provide an increase in angular resolution. This means that the telescope will be capable of distinguishing objects that are close together.
As Dr. Cirasuolo explains, “This will allow the ELT to image exoplanets nearer to the star they are orbiting. We aim to probe planets in the so called habitable zone (where liquid water could exist on their surfaces) and take spectra to analyse the composition of their atmospheres.”
The E-ELT has other goals as well. It aims to probe the formation and evolution of planetary systems, and to detect water and organic molecules in protoplanetary disks around stars as they form. It will look at some of the most distant objects possible—the first stars, galaxies, and black holes—to try to understand the relationships between them.
The telescope is also designed to study the first galaxies, and to chart their evolution over time. As if this list of science goals isn’t impressive enough, the E-ELT holds out the hope of directly measuring the acceleration in the expansion of the Universe.
This video explains the design of the E-ELT and some of its science goals.
These are all fascinating goals, but for many of us the most compelling question we face is “Are We Alone?” Dr. Cirasuolo feels the same. As he told Universe Today, “The ultimate goal is finding signs of life. Certainly the next generation of telescopes will provide a huge leap forward in our understanding of extra solar planets and for the search for life in the Universe.”
The E-ELT won’t be working alone. Other Super Telescopes, like the Giant Magellan Telescope, the Thirty Meter Telescope, and even the Large Synoptic Survey Telescope, will all be working in conjunction to expand the frontier of knowledge.
It may be a very long time, if ever, before we find life somewhere else in the Universe. But by expanding our knowledge of exo-planets, the E-ELT is going to be a huge part of the ongoing effort. A few years ago, we weren’t even certain that we would find many planets around other stars. Now the discovery of exoplanets is almost commonplace. If the E-ELT lives up to its promise, then capturing actual images of exoplanets may become commonplace as well.
About 5,000 cubic meters of rock blasts into the air in this photo taken from a few hundred meters away. Credit: ESO
Talk about starting your astronomy work with a bang! Yesterday’s controlled explosion on the top of Cerro Armazones marked the start of construction preparation for the European Extremely Large Telescope, a 39-meter (128-foot) device intended to teach us more about exoplanets and the universe’s history.
Luckily for those of us who couldn’t make it to Chile, the European Southern Observatory gave us some pictures and video of the explosion in action. These in fact are taken from just a few hundred meters away, much closer than delegates got yesterday during the groundbreaking ceremonies. Watch the videos below.
First light on E-ELT isn’t expected for another decade, but there will be lots more work to look forward to in the coming weeks, months and years. More explosions will continue to remove the top of the mountain and make it level for the telescope, and the design of the large telescope will be finalized.
The top of Cerro Armazones in Chile is blown off June 19, 2014 for the European Extremely Large Telescope. Credit: Vine / ObservingSpace
All’s clear for a huge telescope to start construction on a mountaintop in Chile! That puff you see is the top of Cerro Armazones getting a haircut, losing many tons of rock in just a few seconds. The aim is to clear the way for the European Extremely Large Telescope, a 39-meter (128-foot) monster of a telescope to occupy the mountain’s top. Once completed later this decade, the optical/near-infrared telescope has an ambitious research schedule ahead of it. It will search for planets that look like Earth, try to learn more about how nearby galaxies were formed, and even look for the mysterious dark energy and dark matter that pervade our universe. Construction is being overseen by the European Southern Observatory, which provided an enthusiastic livetweet of the process. You can learn more about E-ELT on ESO’s webpage here. Thanks to @observingspace for posting a Vine of the explosion. Below is an ESO video showing preparations for the blast.
#EELTblast wasn’t a big boom from Paranal, but its significance is Earth-shattering. Thank you for being part of it! Close-up views coming — ESO (@ESO) June 19, 2014
Artist's conception of the E-ELT (left) and Very Large Telescope compared with the Giza Pyramids. Credit: ESO
While we space geeks are lucky enough to watch rocket launches regularly, it’s not often we get to see a mountain top being blown off for the sake of astronomy!
Tomorrow, the European Southern Observatory plans an event centered on a blast on Cerro Armazones, a 3,060-meter (10,000-foot) mountain in Chile’s Atacama Desert. The goal is to make way for construction of the European Extremely Large Telescope, which as its name implies will be a monster of an observatory. Read below for details on how to watch live.
“The E-ELT will tackle the biggest scientific challenges of our time, and aim for a number of notable firsts, including tracking down Earth-like planets around other stars in the ‘habitable zones’ where life could exist — one of the Holy Grails of modern observational astronomy,” ESO states on its page about the 39-meter (128-foot) optical/near-infrared telescope.
The set-up crew for the E-ELT blast looks at Cerro Armazones. Credit: ESO
“It will also perform ‘stellar archaeology’ in nearby galaxies, as well as make fundamental contributions to cosmology by measuring the properties of the first stars and galaxies and probing the nature of dark matter and dark energy.”
We’re sure astronomers can hardly wait for operations to start in the next decade or so. ESO will livetweet the event (also follow the hashtag #EELTblast, where you can ask questions) and watch the entire event live tomorrow here, starting around 12:30 p.m. EDT (4:30 p.m. UTC).
In related news, the last of the Atacama Large Millimeter/submillimeter Array’s (ALMA’s) 66 antennas recently arrived at the ALMA site, which is 5,000 meters (16,400 feet) high on the Chajnantor Plateau in the Atacama Desert of northern Chile. This ESO telescope was officially inaugurated last year.
View of the Atacama Large Millimeter/submillimeter Array (ALMA) site, which is 5,000 meters (16,400 feet) on the Chajnantor Plateau in the Atacama Desert of northern Chile. Credit: A. Marinkovic/X-Cam/ALMA (ESO/NAOJ/NRAO)
Lasers like this one, at the VLT in Paranal, help counteract the blurring effect of the atmosphere. Powerful arrays of much larger lasers could hide our presence from aliens. (ESO/Y. Beletsky)
As the chill of winter settles into the northern hemisphere, fantasies of down-south travel pervade a lot of people’s dreams. Well, here’s a virtual journey to warm climes for astronomy buffs: a beautiful, music-filled timelapse of several European Southern Observatory telescopes gazing at the heavens in Chile.
Uploaded in 2011 (but promoted this morning on ESO’s Twitter feed), the timelapse was taken by astrophotographers Stéphane Guisard (also an ESO engineer) and José Francisco Salgado (who is also an astronomer at Chicago’s Adler Planetarium.) Telescopes include:
Artist's impression of the European Extremely Large Telescope. Credit: ESO
[/caption]
The world’s largest optical/infrared telescope has been given the initial go-ahead to be built. Called the European Extremely Large Telescope (E-ELT) this long-proposed new ground-based telescope will have a 40-meter main mirror and observe the universe in visible and infrared light, making direct images of exoplanets, perhaps find Earth-sized and even Earth-like worlds, and study the first galaxies that formed after the Big Bang.
“This is an excellent outcome and a great day for ESO. We can now move forward on schedule with this giant project,” said the ESO Director General, Tim de Zeeuw.
At a meeting in Garching, France this week, the ESO (European Southern Observatory) Council approved the E-ELT program, with 6 out of 10 countries giving firm approval and four gave “ad referendum” approval, meaning that they needed an official green light from their governments. With that approval, officials are hopeful the E-ELT could start operations by the early 2020’s.
The new super-large eye on the sky will be built at Cerro Armazones in northern Chile, close to ESO’s Paranal Observatory.
The cost is expected to be $1.35 billion USD (1.083-billion-euro)
“World-leading projects of this kind inspire us all and are hugely effective in bringing young people into careers in science and technology,” said David Southwood, president of the Royal Astronomical Society.
This type of telescope has been on the priority list for astronomy by scientists around the world.
The E-ELT will gather 100 million times more light than the human eye, eight million times more than Galileo’s telescope which saw the four biggest moons of Jupiter four centuries ago, and 26 times more than a single VLT telescope.
“The E-ELT will tackle the biggest scientific challenges of our time, and aim for a number of notable firsts, including tracking down Earth-like planets around other stars in the ‘habitable zones’ where life could exist — one of the Holy Grails of modern observational astronomy,” the ESO said.
ESO said that early contracts for the project have already been placed. Shortly before the Council meeting, a contract was signed to begin a detailed design study for the very challenging M4 adaptive mirror of the telescope. This is one of the longest lead-time items in the whole E-ELT program, and an early start was essential.
Detailed design work for the route of the road to the summit of Cerro Armazones, where the E-ELT will be sited, is also in progress and some of the civil works are expected to begin this year. These include preparation of the access road to the summit of Cerro Armazones as well as the leveling of the summit itself.
Need a new desktop image? Usually the Very Large Telescope on Cerro Paranal in Chile provides us with stunning views of the cosmos. This image, however, is a gorgeous view of the observatory itself. As the Moon was setting after a long night of observing, ESO staff member Gordon Gillet welcomed the new day by capturing this stunning image from 14 km away. This image is not a montage or computer-generated (such as the infamous ‘Moon and Sun over the North Pole‘ urban legend)
The ESO website explains:
The Moon appears large because it is seen close to the horizon and our perception is deceived by the proximity of references on the ground. In order to get this spectacular close view, a 500-mm lens was necessary. The very long focal length reduces the depth of field making the objects in focus appear as if they were at the same distance. This effect, combined with the extraordinary quality of this picture, gives the impression that the Moon lies on the VLT platform, just behind the telescopes, even though it is in fact about 30,000 times further away.
Interestingly, Gillet took the image from the road leading to the nearby Cerro Armazones, the peak recently chosen by the ESO Council as the preferred location for the planned 42-meter European Extremely Large Telescope (E-ELT), which should be open for business by 2018.
