2023-07-13 15:45:37
The Extremely Large Telescope (ELT) of the European Southern Observatory (ESO) is a revolutionary ground-based telescope that will have a primary mirror 39 meters in diameter. ESO’s ELT will be the world’s largest visible and infrared light telescope, in other words, the world’s largest eye on the sky. The project, of great technical complexity, is advancing at a good pace and the milestone of 50% progress has already been exceeded.
The telescope sits atop Mount Armazones in the Atacama Desert, where engineers and builders are currently assembling the telescope’s dome structure at an astonishing rate. The steel structure changes its appearance from day to day, but it will soon take on the typical shape of a telescope dome.
The telescope’s mirrors and other components are being built in Europe, where work is also progressing apace. The ELT will have a pioneering optical design consisting of five mirrors. The main one is a giant mirror (M1) made up of 798 hexagonal segments. More than 70% of the raw blocks and segment supports are already manufactured. For their part, the M2 and M3 mirrors have already been cast and are in the polishing process. Advances in the M4 mirror, a flexible adaptive mirror that will adjust its shape thousands of times per second to correct for distortions caused by atmospheric turbulence, are particularly impressive: its six slim petals are fully finished and are being integrated into its structural unit. In addition, the six laser sources, another key component of the ELT’s adaptive optics system, have already been produced and delivered to ESO for testing.
The development or production of all other systems, including the control system and the equipment required to assemble and commission the ELT, are also progressing well. The first four scientific instruments that the telescope will have are in the final design phase and some are about to begin manufacturing. Furthermore, most of the ELT support infrastructure is already on or near Mount Armazones. For example, the technical building that, among other things, will be used for the storage and coating of the different mirrors, is fully built and equipped, while the photovoltaic plant that will supply renewable energy to the ELT facilities started operating last year. .
This image from the end of June 2023, captured with a drone, shows the state of the ELT construction works on Cerro Armazones, in the Atacama desert. The people seen at the bottom give a clear idea of the great size of the dome. Behind the telescope, you can see the shadow of Cerro Armazones, projected on the desert landscape. (Photo: IT. CC BY 4.0)
Construction of the ELT began nine years ago with a blasting ceremony. In 2014, the top of Cerro Armazones was flattened to prepare the ground for the massive telescope.
However, the completion of the remaining 50% of the project is expected to be considerably faster than the construction of the first half, since the latter included the long and painstaking process of finalizing the design of the vast majority of the components that needed to be manufactured. . Additionally, some of the items, such as the mirror segments and their supporting components and sensors, required detailed prototyping and extensive testing before mass production. In fact, the construction was affected by the COVID-19 pandemic, so the works were stopped for several months and the production of many of the telescope components was delayed. With the resumption and optimization of production processes, it is estimated that it will only take five years to complete the construction of the ELT. However, the construction of a telescope as large and complex as this one is not without its risks, until it is finished and operational.
Xavier Barcons, Director General of ESO, said: “ELT is the largest optical and near-infrared ground-based telescope of the next generation of telescopes and the most advanced in its construction. Reaching 50% completion of the work is not minor, given the challenges inherent in large and complex projects like this, and it has only been possible thanks to the commitment of everyone at ESO, the continuous support of the Member States, the participation from our industry partners and consortia responsible for the instruments. I am very proud of this milestone.”
The ELT, whose first observations are expected in 2028, will allow us to address questions such as: Are we alone in the universe? Are the laws of physics universal? How did the first stars and galaxies form? The ELT is likely to make discoveries that radically change what we know about the universe. (Source: IT. CC BY 4.0)
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