The first images of the greatest cosmic movie ever made were released by the Vera C. Rubin Observatory this past summer, and one of the “directors” was UW–Madison physics professor Keith Bechtol.
It’s a story a decade in the making for Bechtol, who served in a leadership role as the observatory’s System Verification and Validation Scientist and has been part of the international collaboration since 2016. He and his UW–Madison research group have been key players on a team of thousands of people that brought the observatory to the main stage. In 2025, its state-of-the-art telescope started taking the first images of the night sky.
“Rubin Observatory is a confluence of technology that allows us to map the universe faster than we’ve ever been able to before,” Bechtol says. “It will catalog more stars, galaxies, and Solar System objects during the first year of science operations than all previous telescopes combined. We will chronicle how the universe changes over time.”
Space-based telescopes like Hubble and James Webb typically focus on one spot for a prolonged time. In contrast, the ground-based Rubin Observatory, positioned on a mountaintop in Chile, is quickly scanning the sky, taking an image with its 3.2-billion-pixel camera every 40 seconds and collecting 20 terabytes of data each night. The observatory is running the “Legacy Survey of Space and Time,” capturing the entire southern hemisphere sky every three nights over its anticipated 10-year run.
In his role, Bechtol was one of five technical group leaders who organized the observatory’s commissioning effort — the building, implementation, and testing that happens on the way to a fully operating observatory. Bechtol oversaw the science deliverables of the project.
“I gather the evidence to show that all components of Rubin Observatory are working together to produce the most detailed time-lapse view of the cosmos ever made,” he says. “I’ve been responsible for anticipating things that could go wrong and helping to address those challenges, designing observation plans, rehearsing observatory operations, and implementing tests of increasing sophistication as we built the observatory. It’s been many years of preparation to get to this point.”
In April, Rubin Observatory achieved “first photon.” In June, people across the globe celebrated the release of the first images, including a viewing party in Chamberlin Hall.
Bechtol and his group will use the data to probe fundamental questions related to dark matter, dark energy, and the early universe.
“We’re using the whole universe as a laboratory to ask big, open questions about the nature of matter, energy, space, and time. What is the universe made of? How did the universe begin? How will it end?” Bechtol says. “We use measurements of strong and weak gravitational lensing and the clustering of galaxies to study dark energy, as well as so-called ultrafaint galaxies to learn about dark matter.”
By Sarah Perdue, Department of Physics