Rubin's secondary mirror is installed

The successful installation of Vera C. Rubin Observatory’s glass secondary mirror marks the end of a long journey for one of the largest convex mirrors ever made. The glass blank and the mirror cell assembly components were shipped to the summit of Cerro Pachón in 2018; in July 2019 the mirror call was coated with protected silver and just recently, in July 2024, it was integrated with the mirror cell.

The Rubin team used a specialised cart to rotate the mirror assembly to a vertical position in order to install the mirror assembly onto the telescope mount. The assembly was then lifted off the cart and onto the telescope mount while maintaining active system control to prevent adding stress to the glass. After bolting the secondary mirror assembly in place, the team connected the mirror cell to the electronics cabinet on the telescope mount and reactivated the mirror’s software control system.

The next step is to re-install the Commissioning Camera, a much smaller version of the LSST Camera that will conduct tests on the optical system. The primary mirror assembly is also due for integration in August, with the LSST Camera due to be installed on the telescope later in 2024. 

The glass mirror is one of the largest convex mirrors ever made.

Credit: Rubin Observatory/NSF/AURA/S. MacBride