Apr 3

World’s Largest Digital Camera for Astronomy is Complete and will travel to Rubin Observatory in Chile

Montage of Rubin Observatory and SLAC LSST Camera
Credit: SLAC National Accelerator Laboratory

This 3,200 megapixel instrument, built by the Department of Energy’s SLAC National Accelerator Laboratory in California, will be brought to Chile soon to begin field testing, and then begin telescope operations in 2025.

After two decades of work at the Department of Energy’s SLAC National Accelerator Laboratory in California, construction of the Legacy Survey of Space and Time (LSST) camera was completed: the largest ever built for astronomy, it will be moved this year to the Vera C. Rubin Observatory, in the Coquimbo Region in Chile.

The Vera C. Rubin Observatory, managed by the Association of Universities for Research in Astronomy (AURA), is mainly funded by the U.S. National Science Foundation and the U.S. Department of Energy. At the heart of the observatory is the 3,200-megapixel camera that will help researchers observe our universe in unprecedented detail. Over ten years, it will generate an enormous trove of data on the southern night sky that researchers will mine for new insights into the universe. That data will aid in the quest to understand dark energy, which is driving the accelerating expansion of the universe, and the hunt for dark matter, the mysterious substance that makes up around 85% of the matter in the universe. Researchers also have plans to use Rubin data to better understand the changing night sky, the Milky Way galaxy, and our own solar system.

“With the completion of the unique LSST Camera at SLAC and its imminent integration with the rest of Rubin Observatory systems in Chile, we will soon start producing the greatest movie of all time and the most informative map of the night sky ever assembled,” said Director of Rubin Observatory Construction and University of Washington professor Željko Ivezić.

To achieve that goal, the SLAC team and its partners built the largest digital camera ever constructed for astronomy. The camera is roughly the size of a small car and weighs around 3,000 kilograms (3 metric tons), and its front lens is over five feet across – the largest lens ever made for this purpose. Another three-foot-wide lens had to be specially designed to maintain shape and optical clarity while also sealing the vacuum chamber that houses the camera’s enormous focal plane. That focal plane is made up of 201 individual custom-designed CCD sensors, and it is so flat that it varies by no more than a tenth the width of a human hair. The pixels themselves are only 10 microns wide.

The construction of this camera for astronomy is a milestone for American technological development. The United States Ambassador to Chile, Bernadette Meehan, sent her “congratulations to the Department of Energy’s SLAC National Accelerator Laboratory at Stanford University and the Vera C. Rubin Observatory on this momentous milestone. The United States is proud of our deep and longstanding collaboration with Chile in the fields of science, technology, and astronomy, including on the Vera C. Rubin Observatory. I look forward to the camera’s arrival in Chile and each milestone that gets us closer to the observatory’s completion”.

The AURA Head of Mission in Chile, Alejandra Voigt, commented, “This camera is unique in the world and its arrival here soon means that Chile remains at the forefront of astronomical research. As managers of this construction project, and of its future operations, we are proud to continue moving towards the commissioning of this telescope, which has been possible thanks to the exceptional work of staff at AURA and the SLAC National Accelerator Laboratory”.

Still, the camera’s most important feature is its resolution, which is so high it would take hundreds of ultra-high-definition TVs to display just one of its images at full size, explained SLAC professor and Rubin Observatory Deputy Director and Camera Program Lead Aaron Roodman. “Its images are so detailed that it could resolve a golf ball from around 15 miles (24 kilometers) away, while covering a swath of the sky seven times wider than the full Moon. These images with billions of stars and galaxies will help unlock the secrets of the Universe.”

This milestone was also recognized by the Minister of Science, Technology, Knowledge and Innovation of Chile, Aisén Etcheverry: “The Vera C. Rubin Observatory camera will be one of the most advanced technological instruments ever installed in Chile. With its unprecedented resolution of 3.2 gigapixels it will capture 20 terabytes of images each night as it unravels the mysteries of dark matter, the birth of galaxies and the most fleeting phenomena in the Universe. This not only confirms our role as the world capital of astronomy, but also reaffirms the central place we play in the implementation of cutting-edge technology, which increasingly pushes the boundaries of what is possible at a technological level.”

Searching for dark matter and dark energy

Once it’s up and running, the camera’s essential purpose is to map the positions and measure the brightness of a vast number of night-sky objects. From that catalog, researchers can infer a wealth of information. Perhaps most notably, the LSST Camera will look for signs of weak gravitational lensing, in which massive galaxies subtly bend the paths light from background galaxies take to reach us. Weak lensing reveals something about the distribution of mass in the universe and how that’s changed over time, which will help cosmologists understand how dark energy is driving the expansion of the universe.

The Scientific Head of Mission of AURA in Chile and Deputy Director of NOIRLab, Stuartt Corder, highlighted that “The arrival of the LSST Camera to Chile is the final major piece needed to complete the Vera C. Rubin Observatory.  Once completed, Rubin will become the flagship of the NOIRLab suite of telescopes, and with Rubin’s transformational capability to observe the sky quickly and repeatedly, our other telescopes will follow Rubin’s discoveries and track the evolution of the dynamic night sky”.

What else do you do with a camera that big?

The same images that reveal details of distant galaxies will help researchers study something closer to home: our own Milky Way galaxy. Many of its stars are small and faint, but with the LSST Camera’s sensitivity, researchers expect to produce a far more detailed map of our galaxy, yielding insights into its structure and evolution as well as the nature of stars and other objects within it. 

Even closer to home, researchers are hoping to create a far more thorough census of the many small objects in our solar system. According to Rubin Observatory estimates, the project may increase the number of known objects by a factor of 10, which could lead to a new understanding of how our solar system formed and perhaps help identify threats from asteroids that get a little too close to the planet.

Finally, Rubin scientists will look at how the night sky is changing – for example, how stars die or how matter falls into supermassive black holes at the centers of galaxies. 

Now that the camera is complete and has been thoroughly tested at SLAC, it will be packed for shipment to Chile, where it will be received at Cerro Pachón at 2,700 meters above sea level in the interior of the Coquimbo Region. The camera will be mounted on the Simonyi Survey Telescope at the Vera C. Rubin Observatory, which will become operational in 2025.

Read the full SLAC press release.