Glass for the LSST primary and tertiary mirrors is loaded into the mold

LSST Mirror Passes High Fire |  The LSST primary/tertiary mirror experienced a successful “high fire” over the weekend of March 28-29, reaching a peak temperature of approximately 1165°C (2125°F).  The LSST mirror will now anneal and cool gradually to room temperature over the next 100 days in the slowly rotating oven at the UA Steward Observatory Mirror Lab, and will be removed in mid-August to begin grinding and polishing.

Image credit: R. Bertram/Steward Observatory and LSST Corporation