Due to problems experienced during the construction of the Extremely Large Telescope (ELT), its commissioning will take place a year later than planned. This is stated in a report published on the website of the European Southern Observatory (ESO).
The largest observatory in the world
The name Extremely Large Telescope is not an exaggeration. The ELT will indeed be the largest ground-based telescope in history and will likely hold that title for quite some time.
Once operational, the ELT will be able to collect 100 million times more light than the human eye and 13 times more than the largest operating optical telescopes. This will provide answers to some of the unsolved questions about our Universe. For example, how the first stars and galaxies were formed. The ELT will also be able to take direct images of extrasolar planets.
The key to this will be the advanced optical system. The ELT’s main mirror has a diameter of 39 meters and consists of 798 segments. It has a total area of 978 m² and a mass of 132 tons. It is the largest mirror ever built for a telescope.
The same can be said for its secondary mirror, which has a diameter of 4.2 meters and a mass of 3.5 tons. It will collect reflected light and redirect it to mirrors M3, M4 and M5. These, in turn, will direct it to the ELT scientific instruments. The 2.4-meter-long M4 will be the largest mirror with adaptive optics ever built. Its surface will be able to deform up to 1,000 times per second to correct for atmospheric turbulence and possible vibrations caused by the telescope’s rotating structure or strong winds.
All of this huge optical system will be placed in a giant rotating dome. Its height will be 80 meters and its mass will be 6100 tons. It will be able to rotate 360 degrees with the help of rail trucks.
Challenges in ELT construction
Given the grand scale of the project, technical difficulties and problems were almost inevitable. And they did occur.
A statement published on ESO’s website said that the main reasons for the schedule delay were severe weather conditions at the construction site (it is being built on top of the Cerro Armazones mountain in Chile’s Atacama Desert), equipment failure, and delays in technological developments. Due to this, the commissioning of the ELT will take place later than planned.
According to the updated schedule, the ELT will see its first light in March 2029. After that, it will be calibrated, and scientific instruments will be mounted on it. If all proceeds as planned, the telescope will begin regular science observations in December 2030.
Previously, we reported on how plans to build an industrial complex in the Atacama Desert could jeopardize the future of ELT.
