SCHOTT is part of the new mega project of the European Southern Observatory (ESO): the Extremely Large Telescope, ELT for short, that will have a main mirror 39 meters in diameter and is currently being built in Chile. These dimensions will make it the largest ground-based optical telescope in the world for visible and near-infrared light ... We are “extremely” happy to be part of it!

On this platform, you will find news, stay informed about important milestones of the project and get exciting and exclusive insights into our contribution to the new mega telescope. Follow us on social media too!

Discover the innovation story


The Extremely Large Telescope will be a "window into distant galaxies". SCHOTT’s ZERODUR® glass-ceramic ensures that crisp images are available to help unlock the mysteries of the universe. We have now summarized all important information about SCHOTT and the ELT in an innovation story.

“Smoothing” starlight


Adaptive Optics: How extremely sharp images are generated by an ultra-thin telescope mirror. 
Images taken by the earth-bound mega-telescope will be 15 times sharper than those taken by the Hubble Space Telescope.
M1 ELT cast

SCHOTT begins manufacturing primary mirrors for ELT [video]


The SCHOTT melting team has started casting the first mirror segments that will make up the 39-meter primary mirror (M1) of the ELT. To make the segments, liquid glass heated to over 1400 degrees Celsius will be poured directly into molds, and transferred into a cooling furnace and subjected to a ceramicization process lasting several weeks. Take a glance at SCHOTT's unique production process.
SCHOTT & the ELT: Everything you need to know in 6 minutes

SCHOTT & the ELT: Everything you need to know in 6 minutes [video]


With a primary mirror diameter of 39 meters and a building height of 85 meters, the ELT is a project of superlatives. But it is not just the sheer scale of the building and its instruments that have the ability to impress. The construction processes are also outstanding. We have prepared a short movie that explains the challenging ZERODUR® production in six minutes, and sheds a light on the sophisticated logistics.
SCHOTT Innovation Roundtable China 2017

Innovation Roundtable in China about the ELT


On July 11, SCHOTT hosted an Innovation Roundtable for Chinese media in Beijing. The event focused on the ELT and SCHOTT’s contribution to this project. Furthermore, the participants learned how specialty glass and glass-ceramic can attribute to ambitious Chinese projects in the area of astronomy space.
SCHOTT to equip the main mirror of the world’s largest telescope with ZERODUR® glass-ceramic

SCHOTT to equip the main mirror of the world’s largest telescope with ZERODUR® glass-ceramic


The gigantic 39-meter primary mirror for the Extremely Large Telescope (ELT) will soon be made up of 798 ZERODUR® glass ceramic components. SCHOTT is set to deliver a total of 949 mirror substrates, including spares, made of ZERODUR® to the European Southern Observatory (ESO).
4-meter mirror blank cast for the ELT project

4-meter mirror blank cast for the ELT project


The ELT team of SCHOTT Advanced Optics cast the 4.25-meter secondary mirror substrate (M2) for the Extremely Large Telescope (ELT) mid of May.
ELT site Chile: Land of extremes

ELT site Chile: Land of extremes


After careful consideration, the ESO selected Chile as the site of the world’s largest telescope. Optimal conditions for astronomical observation were required.
SCHOTT New CNC machine

“Extremely” precise


New CNC machine enables highly accurate processing of mirror components for the Extremely Large Telescope (ELT).

Capacity expansion in record time


Interview about the challenges of constructing the second ZERODUR® glass-ceramic melting tank and perfect teamwork.
SCHOTT Infographics E-ELT optical system

The optical system of the ELT and the role of ZERODUR®


This infographics shows the novel 5-mirror optical system of ESO's Extremely Large Telescope (ELT) and the position of the ZERODUR® mirror substrates.
SCHOTT contract M2 & M3 mirror

Unexplored depths: the world’s largest telescope will peer out into space with technology from Mainz


SCHOTT has been awarded a contract for the production of mirror substrates for the secondary (M2) and tertiary mirrors (M3) of the Extremely Large Telescope. M2 will be the largest convex mirror ever produced.