World's Largest Digital Camera Built in the Bay Area to Illuminate Mysteries of the Universe

Engineers and scientists completed building a camera the size of a family mini-van, capable of capturing large swaths of the night sky in exquisite detail.

The camera, assembled at SLAC National Accelerator Laboratory in Menlo Park, is now on the cusp of doing what scientists and engineers have spent 20 years dreaming, designing, building and testing it to do: take a 10-year-long movie of the night sky from its perch atop a mountain in the Chilean Andes.

In May, the camera will be shipped to its final home, the Vera C. Rubin Observatory in Chile, named for an American astronomer and paired with a custom-built telescope designed to go with it.

No other survey of this caliber has been completed since the 1950s when the Palomar Observatory Sky Survey photographed the entire Southern Hemisphere. The survey will generate a vast trove of images, allowing astronomers to study dark matter, a mysterious type of mass that does not interact with light or any known particle. It will also explore dark energy, an even more mysterious force that seems to be accelerating the expansion of the universe — and a lot more.

“To know that this stuff — is it even a stuff? We don’t know — it makes up 70% of the universe,” said Aaron Roodman, a professor of particle physics and astrophysics at SLAC, who also led the effort of putting the camera together and testing it. “It’s just a fantastic mystery that we’ll be able to study that in multiple different ways using data from Rubin.”

The camera will capture 3,200 megapixels per shot; its images are so detailed that it can see a golf ball from about 15 miles away. The survey should observe an estimated 20 billion galaxies — a significant fraction of the galaxies in the observable universe — providing incremental results.

“You can study how galaxies evolve. Many of those galaxies change in brightness. We’ll be able to detect that because we’ll observe them so many times,” almost a thousand times throughout the survey, said Roodman, who specializes in studying dark energy.

Our galaxy and its billions of stars will also be captured, enabling studies of how the Milky Way was formed and of dark matter — one of the other big mysteries in science today — that makes up 25% of it and everything else in the universe.

“And we don’t know what it is either,” Roodman said.

Asteroids, comets and supernovae — will all be captured by the massive camera and its telescope. Will exoplanets also be studied?

“I won’t be surprised at all if clever people figure out ways to use the data from the Rubin Observatory to hunt for exoplanets,” Roodman said, adding that one of the nice things about the project is the data has no proprietary period — that is, no period where a certain group of scientists will hold onto it — mining it for discoveries before sharing.

“We don’t have that. The data becomes public, available to the whole U.S. science community and select international partners right away,” Roodman said. “I definitely expect clever people to find ways to use it that I can’t tell you today.”

Much of the data will also be publicly available, allowing citizen scientists and night sky aficionados to enjoy its pictures. Some of the scientists who worked on the camera itself are excited about that aspect.

“I think it’s really neat,” said Andrew Rasmussen, a research scientist at SLAC and one of the camera’s instrument scientists. “I have a young daughter who I hope to get online looking at pictures from the camera.”

Parking Maseratis

Putting the Legacy Survey of Space and Time camera together was an unprecedented challenge, Roodman said, because no other piece of equipment like it has been built before.

“We really pushed the edge of what’s possible to get the most performance possible out of the camera,” he said.

One of the most difficult aspects was the installation of the camera’s sensors. The work, Roodman said, was like parking a Maserati in between two other Maseratis, with less than an inch to spare on either side.

Within the camera are 201 individual image sensors, each a 16-megapixel device, 4 centimeters by 4 centimeters, and they could only be held by the back for fear of ruining them.

“So the sensors were pretty big. And we kept the gaps between them to half a millimeter. And that turned out to be actually very difficult mechanically to put together, to assemble,” Roodman said.

It took hours in a clean room for just one of the 25 total rafts to be carefully placed inside the body of the camera. Each raft was a million-dollar tower of electronics topped by an array of sensors.

For the work, the team constructed a robotic arm to assist with the placement of the sensors, but the robot was not precise enough to place them on its own. One person would monitor the location of the individual rafts in the X, Y and Z plane and would call out to the arm operator, “500 microns minus X” or “250 microns minus Y!”

Despite the challenge, the LSST — the world’s biggest digital camera, verified by the Guinness Book of World Records — was completed in April. (They called it the “highest-resolution” camera.)

Preparing for primetime

The camera will live at an observatory named after Vera Rubin. Her work in the mid-60s provided convincing evidence for the existence of dark matter. Before her, dark matter had been a concept, but not one that was taken seriously.

Rubin, despite her success, encountered barriers as a woman working in science and sought to help other women enter the field.

Today, officials at the Rubin Observatory say they seek to continue that spirit and welcome all into the field of science, including people of color, nonbinary people, people with disabilities and those from differing socioeconomic backgrounds.

The Rubin research program is ramping up, with meetings and workshops this spring and summer about how to use data from the observatory, including how to teach astronomy using Rubin images and new tools for analysis.

“One of the exciting things about the Rubin Observatory is that the science program is so very broad,” Roodman said. “And it’s broad because we’re taking pictures of everything. The way a lot of telescopes work is, people write proposals and they are interested in looking at a particular object or at a particular kind of object. We’re not doing that. We are going to take pictures of everything, by the end we’ll have seen every part of the Southern Hemisphere sky almost a thousand times.”

The first images are expected to land in the spring of 2025.