NOIRLab - Rubin Observatory Reaches Major Milestone

Vera C. Rubin Observatory’s Simonyi Survey Telescope ready to receive optical components

Vera C. Rubin Observatory has passed a major construction milestone: the telescope structure is ready to be outfitted with a full-size replica of its 8.4-meter mirror and stand-ins for its 3200-megapixel LSST Camera and other critical optical components. This major milestone means that Rubin Observatory is on track to help probe the mysteries of dark matter, study the fundamental nature of dark energy, document the dynamic Universe, and explore other grand challenges of cosmology.

The NSF-funded Vera C. Rubin Observatory has reached a major construction milestone with the completion of the telescope structure, known as the Telescope Mount Assembly. This designation means that the telescope, named the Simonyi Survey Telescope, is on track to receive the observatory’s massive 8.4-meter mirror, 3200-megapixel LSST Camera (the largest digital camera ever constructed for astronomy, funded by the Department of Energy and built at SLAC National Accelerator Laboratory), and other precision optical components. 

Rubin will be a pioneering observatory designed to explore the mysteries of dark matter, study the enigmatic nature of dark energy, and probe many other grand challenges of cosmology, astronomy, and astrophysics. It also will be the first observatory designed to study the changing Universe, essentially making “movies” of the night sky. 

These remarkable capabilities come, in part, from the telescope’s revolutionary design. Though Rubin is structurally similar to other 8-meter-class telescopes, it is considerably shorter, giving it a much lower center of gravity, which allows it to quickly and precisely move from one area of the sky to another. Such ease of movement is essential to capture fleeting, transient events, such as gamma-ray bursts and bright flashes of supernovae.

One of Rubin’s primary science goals is to conduct a decade-long survey of the optical sky called the Legacy Survey of Space and Time. This unprecedented campaign, starting in 2025, will collect and process more than 20 terabytes of data each night — and up to 10 petabytes each year for 10 years — to compile detailed composite images of the southern sky. The speed and nimble design of the telescope will allow it to survey the entire visible southern sky every few nights and will essentially create a time-lapse movie of changes over different timescales to learn about the risks from asteroids and many other phenomena in the changing Universe. Over the course of a decade, the LSST Camera will detect and capture images of an estimated 30 billion stars, galaxies, star clusters, and asteroids.

“The Rubin Observatory will not just peer across the Universe and look back in time. It will also have the unprecedented capability of studying the Universe as it changes in real time, from night to night,” said Bob Blum, Director for Operations Vera C. Rubin Observatory with NSF’s NOIRLab, which along with SLAC National Accelerator Laboratory, will support Rubin Observatory in its Operations phase.

The telescope structure was fabricated, assembled, and tested at the UTE/Asturfeito factory in Spain. It was shipped to Chile and installation on Cerro Pachón began in late 2019. This process included the installation of drive motors and utility systems, including kilometers of cables, piping, and hoses that provide electricity, communications, compressed air and coolants to the different parts of the telescope and camera.

With the major hardware in place, the telescope and site software team integrated the software control system that drives the telescope. 

Over the past several months, Rubin’s team of observing specialists has been testing the integrated hardware and software to study how accurately the telescope points and tracks. The Rubin Systems Engineering team has been heavily involved in these and other testing campaigns to ensure the telescope meets its technical requirements and is working as designed. 

Data from these testing campaigns and the Engineering and Facility Database verified that the entire system to date met the required specifications. The telescope structure was then declared ‘substantially complete’, which will soon allow the UTE construction company to officially hand over the telescope to Rubin and over the next weeks move towards final acceptance and contract conclusion. The Rubin summit team is now preparing for the next major systems integration phase: installing the Primary-Tertiary mirror cell and surrogate mirror on the telescope structure.

“It's gratifying that after years of hard work by so many people, we have such a huge accomplishment to celebrate,” said Jeff Barr, Rubin Observatory Telescope and Site Manager.

After more than a decade of planning, development, and construction, Rubin is on track to give astronomers and the public a previously unimaginable view of the dynamic and changing Universe.