Mipa's WB coating chosen for world's largest telescope

ESO's Extremely Large Telescope (ELT) is considered a pioneering achievement in space exploration. The giant telescope is currently being assembled in Chile and is expected to be operational in about five years. It will then become the world's largest visible and infrared telescope.

For the coating of steel structures, ESO has selected coatings from WB Coatings, a brand of Mipa Group, since January 1, 2023. The biggest challenge in choosing the right paint was creating the darkest possible black, matte surface to minimize scattered light and prevent interference during operation. 

A wide range of requirements can be met with WB Coatings' robust epoxy primers, PU topcoats and matching clearcoats. As the construction is carried out by an international consortium, WB products are supplied to the two participating companies in Spain and Italy. The individual steel components are coated there and then shipped to Chile for assembly.

When planning the steel structure, emphasis was placed on keeping the telescope stable in all conditions, including strong winds or earthquakes. The structure must be absolutely stable to maintain precise alignment of components and equipment. But at the same time, it had to be light enough so that the massive ELT didn't collapse under its own weight.

The telescope is located on Cerro Armazones, a 3,046-meter-tall mountain in Chile's Atacama Desert. The ELT will feature a groundbreaking optical design with five mirrors, including a massive 39-meter primary mirror made of 798 hexagonal segments. The other mirror will adaptively adjust and correct distortions caused by air turbulence by changing its shape approximately a thousand times per second.

Meanwhile, the steel dome has taken on the rounded shape typical of telescope domes. Six laser sources, another key component in the ELT optical system, have now been manufactured and delivered to ESO for testing. According to ESO, all other systems and components required to complete the ELT are also currently progressing in development or production. Construction of the ELT began nine years ago with a groundbreaking ceremony in Chile. The remaining 50% of projects are expected to be built at a much faster pace than ELT's first half. The first light image is expected to be released in 2027.