The website of the European Southern Observatory published an image from the Atacama Desert. It shows the process of construction of the central tower of the Extremely Large Telescope (ELT).
The extremely large telescope will be the most powerful optical observatory in history. It will be able to collect 100 million times more light than the human eye and 13 times more than the largest operating optical telescopes. The key will be its advanced optical system, a fragment of which is captured in the photo. The size of a three-story house, the central tower looks impressive on its own, but it’s only a small part of the ELT superstructure.
This skeletal frame will support three of the five ELT mirrors of different shapes and sizes: M3 (at the bottom of the tower), M4 (at the top), and M5 (in the center). Together, they will direct the light captured by the telescope from space to its instruments, which will form images.
Atop the M4’s tower will be the largest adaptive optics mirror 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. This is very important to get the clear images that scientists need for their research.
The M5 mirror, located in the center of the tower, will redirect light to scientific instruments located on the sides of the telescope. It will do this up to 10 times per second to stabilize the images.
Designing the tower proved to be quite a challenge. Since it is attached to the center of the ELT’s main mirror cell, it must be light enough not to deform the mirror structure. At the same time, the frame must be rigid enough to allow the tower to flex only minimally under its weight when the telescope is tilted. With all that said, the wind should pass through the tower to prevent air pockets that can distort the image. But despite all these challenges, the engineers managed to cope with the task and create the right design.
Earlier we covered other large observatories that would be operational in the coming years.
Provided by ESO
