Beacons Beam Sunlight From Atop Golden Gate Bridge's Towers

The  in honor of the last month is in the rearview mirror.

But those in the know have noticed that the light show continues in the form of two heliostats – mirrors dubbed Solar Beacons that reflect sunlight at a predetermined target – from atop the bridge's two towers.

The flashes of light are part of an art installation designed by University of California, Berkeley space scientists for the bridge's birthday. They'll remain atop the bridge through Aug. 30. And according to UC Berkeley officials, anyone can schedule a time for the heliostats to swivel at just the right angle to send four minutes of a "reflected image of the sun anywhere within view of the tops of the orange towers." Schedule a time through the Solar Beason website.

Those in Marin County can see the solar beacon best during the morning and evening, while people in San Francisco can schedule a viewing at pretty much any time of the day, according to school officials.

The heliostats – each about two feet across and consisting of four six-inch-square mirrors – are an art installation proposed by UC Berkeley space scientist John Vallerga to celebrate the 75th anniversary of the completion of the bridge. The project is a collaboration between Vallerga and London-based artist Liliane Lijn.

“This is not something we have ever done before or will ever do again – we don’t let people place art on the bridge,” bridge manager and mechanical engineer Kary Witt said in a statement. “But this is a pretty cool project, especially the technology they’re using, which is based on what they use in space.”

Each mirror assembly is attached to motors that can swivel and tilt to send a reflected image of the sun anywhere within view of the tops of the orange towers. The image of the sun is about 1/2 degree across, which means it will be spread out to more than 90 feet at a distance of about two miles. People will see a bright point of light on the top of each tower, similar in brightness to the sun reflecting off a car mirror.

For more info or to schedule a Solar Beacon, go to the project's website.