Streetlights Go From Yellow To White, But Green Option Hurts Bay Area Astronomers

SAN JOSE (KPIX 5) - San Jose street lights are getting a "green" upgrade, but not all environmental scientists are thrilled about the change.

The dim, yellow bulbs that have lit up the city's streets for years are being replaced with cheaper, brighter LED lights. Astronomers say that change is making their work harder.

Dr. Raja Guha Thakurta, an astronomer at Lick Observatory on Mt. Hamilton, says the old yellow lights are easier for astronomers to filter out. The white LEDs contain all of the colors of the rainbow and essentially mimic sunlight.

"My first reaction, to be honest with you was 'Oh no,'" said Dr. Guha Thakurta. "There is this competing pull of the citizens wanting light to be a certain way, but astronomers needing light to be a different way. As we'll see, there are ways to meet both needs."

Cities say the brighter LEDs help deter crime. They also use 60 percent less power, last longer and will save millions in San Jose alone. The city says they didn't intend to snub astronomers.

"We're dimming our lights between midnight and 5, which allows their needs to be met as well," says Hans Larsen of the San Jose Department of Transportation.

The astronomers at Lick Observatory know a thing or two about changing with the times. They have been around for more than 125 years. They're shifting a lot of their research away from visible light, and they're pioneers in what they call adaptive optics.

"We have techniques that, in real-time, correct for the distortion that the atmosphere puts on the images of stars or galaxies," Dr. Guha Thakurta. "There's a sense of pride that world-class research is going on in this city. And we, as a city, have been able to adapt to make that happen."

San Jose is not the only city in the Bay Area making the upgrade, hundreds of thousands of yellow street lights are being replaced with the LEDs.