‘We have a telescope!’ Rubin Observatory construction team installs its huge mirror

The Vera C. Rubin Observatory’s 8.4-meter Simonyi Survey Telescope in Chile has now been equipped with all three of its mirrors, plus a camera for good measure.

Last week’s installation of the telescope’s combined primary/tertiary mirror represented a major milestone in the observatory’s 15-year-long design and construction effort.

“We have a telescope!” the observatory team declared in updates posted to Instagram, Threads, BlueSky and X / Twitter.

The wide-field telescope, which is named after Microsoft software pioneer Charles Simonyi, is expected to shed light on mysteries ranging from the nature of dark energy and dark matter to the potential existence of an as-yet-unseen “Planet X” in the far reaches of our solar system. (Update: Simonyi and his family attended the telescope’s dedication ceremony on Oct. 4. Read on for details.)

The telescope’s 8.4-meter-wide (27.5-foot-wide) primary/tertiary mirror makes use of a continuous surface with different curvatures that are designed to optimize image resolution inside a relatively compact support structure. The 3.4-meter-wide (11-foot-wide) secondary mirror was installed in July.

When it’s fully up and running, the Simonyi Survey Telescope is expected to generate 20 terabytes of data every night. But the current version of the telescope isn’t yet ready for prime time.

“This iteration has the commissioning camera — a smaller 144-megapixel version of Rubin’s huge, 3,200-megapixel camera — which is used for testing and troubleshooting,” the observatory team noted. “Rubin’s LSST Camera, the biggest digital camera in the world that will #CaptureTheCosmos in science operations, will be installed early next year after our summit staff complete the next round of tests.”

Astronomers at the University of Washington are playing key roles in the Rubin Observatory’s construction and operations. UW’s Zeljko Ivezic is director of Rubin construction. Mario Jurić is director of UW’s DiRAC Institute, which is developing software tools to deal with the torrent of data that will come from the telescope.

James Davenport, the DiRAC Institute’s associate director, said recent milestones are making the approaching start of science operations “feel so real.”

“I used to work at the Apache Point Observatory, where we had ‘only’ a 3.5-meter diameter primary mirror,” Davenport told GeekWire in an email. “I can tell you from experience that there’s nothing more terrifying than moving the BIG piece of glass in and out. This is a complicated dance, and seeing it done so smoothly on the first try with the Simonyi Survey Telescope feels like a good omen for the Rubin Observatory!”

As is usually the case for multimillion-dollar astronomy projects, it’s taking longer than originally planned to finish the observatory. “While good progress was made in many technical systems, activity progressed more slowly than scheduled,” the Rubin team reported in an construction update.

According to the update, work on the primary/tertiary mirror was complicated by “unexpected actuator damage that needed repairs.” The schedule now calls for the commissioning camera to hit a “First Photon” milestone in mid-November, and for the LSST Camera to be placed onto the telescope mount assembly next February.

If all goes according to plan, the Simonyi Survey Telescope and its LSST Camera will achieve “First Light” next June, with full-scale observations for the Rubin Observatory’s 10-year Legacy Survey of Space and Time beginning sometime afterward. But don’t be surprised if the plan faces further revisions down the line.

Update for Oct. 11: Charles Simonyi and his family were on hand Oct. 4 for the telescope’s dedication ceremony at the Rubin Observatory Summit Facility on Cerro Pachón in Chile.

“This marvelous machine — envisioned by Tony Tyson more than 20 years ago and created by hundreds of scientists, engineers, and technicians — will do the the yeoman’s work for thousands of astronomers around the world, leading us to countless new and exciting discoveries,” Simonyi said in a news release. “We are greatly humbled by and proud of the naming of the Simonyi Survey Telescope.”

Simonyi donated $20 million in 2008 to support the construction of the telescope’s primary/tertiary mirror and the creation of a fellowship program. That contribution, plus $10 million from Microsoft co-founder Bill Gates, helped get the ball rolling for the Rubin Observatory. Since then, the National Science Foundation and the U.S. Department of Energy have provided more than $800 million in federal funding for the observatory.

“We are thrilled to honor the Simonyi family’s commitment to advancing astronomical discovery and exploration,” said Zeljko Ivezic, director of Rubin Observatory construction. “Their support has been crucial for the construction of this world-class facility and for the scientists who will use the Simonyi Survey Telescope to better understand our universe.”

In 2022, Simonyi pledged an annual gift of $1 million for 10 years to support early-career researchers engaged in the science that the Rubin Observatory will enable. That gift was matched by funds from NSF, creating the NSF-Simonyi Scholars program,

Previously: Get a wide-angle view of the Simonyi Survey Telescope