The University of Arizona’s Richard F. Caris Mirror Lab makes the largest telescope mirrors in the world and the only large lightweight telescope mirrors. These spin-cast honeycomb mirrors have low mass, high stiffness and rapid thermal response to give the best possible image quality in observatory conditions. The Mirror Lab developed the spin-casting method and rotating furnace that provides a one-piece casting of lightweight mirrors up to 8.4 m diameter. The Lab also developed methods of polishing and measuring mirrors with very short focal length that enable stiff telescope structures and less costly enclosures.

The Mirror Lab has made 8.4 m honeycomb mirrors for the Large Binocular Telescope (2 mirrors), the Rubin Observatory (combined 8.4 m primary and 5.0 m tertiary mirror), and the Giant Magellan Telescope (7 primary mirror segments cast, 3 segments complete). The Lab has also made 6.5 m mirrors for telescopes including the MMTin Arizona and the Magellan Baade and Clay Telescopes in Chile.