Zerodur

Opening of the ELT secondary mirror ZERODUR® blank mould containing the glass at first annealing at the Schott AG 4-meter blank annealing facility in Mainz, Germany.[1]

Zerodur is a lithium-aluminosilicate glass-ceramic manufactured by Schott AG. Zerodur has a near zero coefficient of thermal expansion (CTE), and is used for high-precision applications in telescope optics, microlithography machines and inertial navigation systems.

  1. ^ "Secondary Mirror of ELT Successfully Cast - Largest convex mirror blank ever created". www.eso.org. Retrieved 22 May 2017.