Steward Observatory, Research observatory in Tucson, United States
Steward Observatory is a research facility of the University of Arizona in Tucson, operating telescopes at several sites across the region and beyond. Within the complex, the Richard F. Caris Mirror Laboratory is an active workshop where large optical mirrors are produced for telescopes around the world.
The observatory was founded in 1916 through a private donation and began operations in 1923 with its first large telescope. That early instrument stood out because every one of its components was manufactured within the United States.
The observatory takes its name from Lavinia Steward, whose donation made its construction possible. On campus, it remains a working part of university life, where students and researchers interact daily with active scientific equipment.
Not all areas of the site are open to the public, so it is worth checking in advance which parts can be visited. The Mirror Laboratory offers guided tours, and booking ahead is generally required to secure a spot.
The mirrors made here are not only used by the observatory's own telescopes but are also supplied to some of the largest telescopes on Earth, on multiple continents. The Mirror Laboratory uses a spin-casting technique where glass is melted in a rotating furnace so the mirror's curved shape forms naturally during casting.
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