San Bernardino County history: Big Bear Solar Observatory

"San Bernardino County Update", yellow arrowhead and "SBCounty.gov

A large and white observatory dome near a forested area and lake. — *Dome on the main Big Bear Solar Observatory building viewed from Big Bear Lake. Photo courtesy of Pgoode1943.*

For the first time in nearly 40 years, a total solar eclipse crossed the continental United States on Aug. 21, 2017. During a solar eclipse, the moon passes between the sun and Earth, briefly blocking the sun’s light. Events like this are not only spectacular to observe, but also provide valuable opportunities for scientific study.

One important center for this kind of research is the Big Bear Solar Observatory in the San Bernardino Mountains. The site was established in 1969 by Dr. Harold Zirin, a professor of astrophysics at Caltech, with support from a Caltech grant and donations from the Fleischmann Foundation. The observatory remains in operation today.

Big Bear Lake provides an ideal setting for solar observation because the surrounding water helps reduce heat distortions that can interfere with telescope imaging. The area also has an average of 300 clear days a year, and it sits above sea level, which allows for clearer and more precise observations.

Solar eclipses have been recorded for thousands of years with the earliest known observation dating back to 1217 BCE. Today, scientists use ground and space-based instruments to study these rare events, including powerful telescopes in observatories.

The Big Bear Solar Observatory is home to the 1.6-meter Goode Solar Telescope, which is one of the most powerful solar telescopes in the world. The telescopes and instruments at the observatory are specifically designed to study the sun’s surface and activity.

Even before construction was complete, the site contributed to history by observing the Apollo 11 Moon Landing. For more information, including panoramic virtual tours and videos, please visit the observatory’s website.

The information in this historical feature was originally part of a video series produced by the Assessor-Recorder-County Clerk’s office.

Additional County Update News – May 7, 2026