Hundreds of people gathered on the American River levee across Sacramento State’s Hornet Bookstore for a solar eclipse viewing party Monday.

The event, which started at 9 a.m. and ended around 10:30 a.m., was hosted by physics professor Rodolfo Barniol Duran and the physics department.

A solar eclipse is the rare occurrence when the moon passes directly between the sun and the Earth, blocking sunlight and casting a shadow on Earth.

The last total solar eclipse visible from the lower 48 states happened in 1979 and it only covered a few states in the Pacific Northwest. Monday’s eclipse was coast-to-coast, stretching from the coast of Oregon to the edge of South Carolina.

As visible from Sacramento, the moon eclipsed 80 percent of the Sun.

“The eclipse was at its optimal at around 10:17 a.m. and it caused the wind to pick up a little” Duran said. “Now, the percentage (of the eclipse) is dropping. Everything will get a little brighter and hotter.”

There were also attendees who brought their own welding glasses, lenses, X-ray scans or homemade pinhole projectors, which reflect the eclipse through a tiny hole into a cereal or cardboard box.

Heavy clouds in the Bay Area forced a few UC Berkeley’s engineering students — who came with their own pinhole projectors — to drive to Sac State to view the eclipse.

Missed this year’s eclipse? Then mark your calendar. According to NASA, another total solar eclipse will pass through the U.S. in 2024, projected to stretch from Northeast to Southwest.

More tweets from the event below:

Crowd stretches from the levee near Hornet Bookstore to the Guy West Bridge entrance. #Eclipse2017 pic.twitter.com/AeBRJtamv8

— Vu Chau (@vchau2020) August 21, 2017