Wisconsin science, industry play critical roles in creating powerful new Rubin Observatory

The NSF-DOE Rubin Observatory is a groundbreaking achievement for astronomers. Scientists and companies in Wisconsin made the endeavor possible.

Light from faraway galaxies can show us what the universe was like billions of years ago. But the movements and mysteries of those galaxies tell physicists that we still don’t know what makes up the vast majority of the universe.

“How did it begin? When will it end? What is it made of?”

Keith Bechtol, a physics professor at University of Wisconsin-Madison, said these are some of the questions scientists will try to address with a new observatory in Chile featuring the biggest camera ever built.

The NSF–DOE Vera C. Rubin Observatory, funded by the U.S. National Science Foundation and U.S. Department of Energy’s Office of Science, released the first set of images on June 23. The stunning images represent the fruits of a decades-long effort to push the study of the cosmos well past its current limits.  

Building the Rubin Observatory, which sits on a summit in Chile’s Andes Mountain range, spanned three decades and involved parts and people from three continents. Some of the most important support came from Wisconsin.

‘Visionary’ Rubin Observatory provides detailed look at the cosmos

Beginning in October 2025, the Rubin Observatory will embark on the Legacy Survey of Space and Time (LSST). Over the next 10 years it will scan the entire Southern Hemisphere sky about 800 times, providing the most detailed look at the universe to date.

The plan going forward sounds deceptively simple.

Getting to the starting point was anything but that.

“The whole idea for the (Rubin) observatory was so visionary when it was conceived (in the 1990s) that many of the technologies didn’t exist at that time” said Bechtol.

Bechtol served as the System Verification and Validation Scientist for the international team in charge of the Rubin. He oversaw much of the testing that ensures scientists will reliably get the high-quality data they are seeking.

Observatories usually face trade-offs between how big an area they scan, the resolution of the photos they take and how fast they can take them. The scientists designing the Rubin attacked these challenges on all three fronts.

The Simonyi Survey Telescope installed uses an innovative mirror system to reflect incoming light onto a camera the size of a car. After scanning one piece of the sky, the whole system rapidly spins to look in a different direction, rotating in coordination with its protective dome while maintaining near perfect alignment of the mirrors.

According to Bechtol, displaying one image at full resolution would require enough high-definition TVs to cover a basketball court.

The final step in building the Rubin — installing the 80-ton mirror system — was made possible by the Milwaukee-based company PFlow Industries.

Pieces of the telescope were assembled at a staging area but needed to be raised five stories to be installed in the dome. PFlow custom-built a lift capable of moving critical equipment from the assembly area to the dome. A video shared by Rubin Observatory shows this lift in action.

During and after construction, Bechtol organized a series of “rehearsals” to simulate how the Rubin will operate. He accounted for details including the workflow of operating it, the challenge of transferring massive amounts of data from the summit, and even making sure the summit hotel was staffed and had food for its residents.  

After nearly 30 years of dreaming, designing, building and testing, the first images from Rubin Observatory arrived.

Scientists share new images with the public

UW-Madison hosted a First Look Party on June 23 to view these images with the public. Nearly 100 people gathered in a physics department auditorium to watch a livestream of a press conference in Washington, D.C., before participating in a panel discussion with Bechtol and other scientists who will use data from the Rubin.

Even though Monday was the first chance for the public to see the images, some of the scientists involved in the project had a sneak peek.

“I woke up in bed and saw messages” that the first images had come in, said Miranda Gorsuch, a graduate student at UW-Madison who has Bechtol as an advisor. “It was like waking up from a dream.”

Gorsuch plans to use the data to study the structure of the universe and how it evolves over time.

Rubin Observatory is named after Vera C. Rubin, an astronomer who first provided observations suggesting we might not be able to see most of the matter making up the universe. Understanding the properties of this “dark matter” is one of the top priorities for scientists who will use the collected data.  

But there is so much more to learn; the Rubin is already showing outer space in incredible detail. Just one small slice of our solar system imaged by Rubin Observatory already led to the discovery of 2,000 new asteroids. In one image of the full field of view, scientists detected 10 million galaxies — many for the first time. By repeatedly scanning the sky, scientists hope to use the Rubin as an alert system for rare events, like supernovae, which they can then observe in more focused follow-up studies.

“This is when science works best – when you have this interplay” between new discoveries and the new questions they raise, Bechtol said.

“There’s a science case (for building the Rubin), but any time you do this, there is also a set of questions you haven’t thought to ask yet” said Eric Wilcots, dean of the College of Letters and Science at UW-Madison.

While UW-Madison was just one of many universities involved in the international project, Wilcots believes its participation will inspire future scientists and attract them to Wisconsin.

Both Bechtol and Wilcots stressed the importance of sustained financial support from the NSF and DOE to bring the project to fruition.

Rob Morgan was one of the first graduate students advised by Bechtol, working on a Dark Energy Survey that served as a precursor to Rubin Observatory. According to Morgan, the Rubin is the culmination of the astronomy field’s shift towards a “big data” approach. Now, Morgan applies the skills he learned as an astrophysicist to his work at Google’s office in Madison.

“Google is where ‘big data’ is done for the rest of the world,” said Morgan.

This week’s image release represented a beginning. Scientists will spend years collecting and analyzing data. Still, the opening provided a moment worth cherishing.

“We don’t get a lot of observatory openings,” said Alyssa Jankowski, who recently completed an undergraduate degree at UW-Madison. “It’s important to celebrate.”