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SCHOTT Produces 500th M1 Primary Mirror Segment for Extremely Large Telescope

July 13, 2022, Mainz, Germany

  • SCHOTT has produced its 500th M1 primary mirror segment for the European Southern Observatory’s Extremely Large Telescope in Chile.
  • The company’s manufactures its glass ceramic ZERODUR® mirror blanks in series in accordance with the highest surface quality demands for ESO.
  • Specialty glass manufacturer SCHOTT is producing 949 M1 hexagonal segments for the world’s largest optical telescope, which is expected to see its first light by the end of 2027.

SCHOTT has produced its 500th ZERODUR® mirror blank for the M1 primary mirror of the European Southern Observatory’s Extremely Large Telescope. The ELT, which is scheduled to see its first light in 2027, will be the world’s largest eye on the sky. For the 39-meter M1 primary mirror, SCHOTT is producing 798 hexagonal segments made of its ZERODUR® glass ceramic, as well as an additional 133 spare and 18 prototype segments. Considered the gold standard for segmented telescope mirror substrates, ZERODUR® also has many high tech and industrial applications due to its near zero thermal expansion coefficient.

International technology group SCHOTT has produced its 500th ZERODUR® mirror blank as part of its contract to supply segments for the M1 primary mirror of the European Southern Observatory’s Extremely Large Telescope. Currently under construction on Cerro Armazones in Chile’s Atacama Desert, the ELT will be the largest optical telescope in the world with a 39-meter primary mirror and will see its first light in 2027. SCHOTT signed a contract with ESO in 2017 to supply at total of 949 ZERODUR® mirror blanks for the ELT’s M1 primary mirror (including 798 mirror blanks, 133 spare and 18 prototypes segments), and delivered its first prototypes in 2019. Series production for the ELT at SCHOTT’s Mainz, Germany headquarters began in 2020, and the final mirror blanks will be produced in early 2024. In addition to the M1 mirror blanks, ZERODUR® will also feature on the ELT’s convex M2 mirror (4.2 meters), concave M3 mirror (3.8 meters), and adaptive M4 mirror (2.4 meters). After production by SCHOTT, the mirror blanks are shipped to French company SAFRAN Reosc for polishing. Thomas Werner, Head of the ELT Project at SCHOTT welcomed the production milestone, saying: “We are very proud to help shape the future of astronomy by supporting the European Southern Observatory in their important work on the ELT.”

ZERODUR®: An Exceptional Material

ZERODUR® glass ceramic has a long history of success both in astronomy and in industry applications due to its extremely high thermal and mechanical stability. First produced by SCHOTT in 1968 in collaboration with Germany’s Max Plank Institute for Astronomy, ZERODUR® also plays a key role in a large number of demanding high-tech applications requiring exceptional precision, such as navigation systems and lithography equipment for integrated circuit manufacturing. In addition to its near zero thermal expansion and extraordinary homogeneity, its mechanical and chemical properties enable strong performance under extreme conditions on earth or in space. SCHOTT draws on its long experience mass-producing its glass ceramics for industrial applications in its collaboration with ESO on the ELT mirror blanks. The company has previously supported ESO on other projects, such as the Very Large Telescope, for which it manufactured 8.2-meter ZERODUR® primary mirrors for four unit telescopes.

Next week, SCHOTT product management and application representatives will be presenting on ZERODUR® at the SPIE Astronomical Telescopes + Instrumentation conference in Montreal, Canada from 17. to 22. July.

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Pioneering – Responsibly – Together.

These attributes characterize SCHOTT as a manufacturer of high-tech materials based on specialty glass. Founder Otto Schott is considered its inventor and became the pioneer of an entire industry. Always opening up new markets and applications with a pioneering spirit and passion – this is what has driven the #glasslovers at SCHOTT for more than 130 years. Represented in 34 countries, the company is a highly skilled partner for high-tech industries: Healthcare, Home Appliances & Living, Consumer Electronics, Semiconductors & Datacom, Optics, Industry & Energy, Automotive, Astronomy & Aerospace. In the fiscal year 2021, its 17,300 employees generated sales of 2.5 billion euros. SCHOTT AG is owned by the Carl Zeiss Foundation, one of the oldest foundations in Germany. It uses the Group's dividends to promote science. As a foundation company, SCHOTT has anchored responsibility for employees, society and the environment deeply in its DNA. The goal is to become a climate-neutral company by 2030.

Press contact:
Elisabeth Harvey
Communications Manager
+49 1511 083870

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