Rubin Observatory's 8.4-meter mirror is coated

Rubin Observatory’s 8.4-meter combined primary/tertiary mirror was coated with protected silver in April 2024. The reflective coating was applied using the observatory’s onsite coating chamber, which will also be used to re-coat the mirror as necessary during Rubin’s 10-year Legacy Survey of Space and Time. This video shows the process of moving the glass into the coating chamber, applying the four coating layers (nickel-chromium, silver, nickel-chromium, and silicon nitride), and revealing the mirror.