PALOMAR MOUNTAIN - On a recent Sunday evening, as the sun dipped below the horizon and a chill set in, the Palomar Observatory southeast of Temecula whirred to life.
As the white dome above the venerable 200-inch Hale telescope yawned open, two astronomers in the observatory's belly sat before a bank of computer screens, hoping one of the faint gray splotches became the next big discovery.
For more than 50 years, the observatory 5,600 feet above north San Diego County has been a beacon in the astrophysics world, helping scientists track asteroids, exploding stars and other planets' atmospheres. One discovery led to the demotion of Pluto from a planet to dwarf planet in August.
But astronomers who use the facility are facing a growing menace that threatens new discoveries: Bright lights from rapidly expanding communities in southwest Riverside County, and elsewhere are interfering with astronomers' views of outer space.
Palomar sent a plea to Riverside County to raise awareness about the problem and to urge the county to toughen its light-pollution ordinance, regulating the types of lights businesses and homes can use and when. The ordinance, whose stated intent was to prevent undesirable light rays from having a "detrimental effect" on astronomy research at Palomar, has not been updated since it was adopted in 1988.
When city lights reach the atmosphere, water droplets and dust particles scatter the light, creating a haze or "sky glow" effect that scientists liken to white noise on a TV screen. The more noise, the tougher it gets to identify objects.
Too much bright light, such as seen on the horizon, is interfering with Palomar Observatory's ability to study deep into the nighttime sky, spokesman Scott Kardel said.
"I've been spending years searching for things out on the edge of the solar system, but the edge is actually affected by light pollution," said Caltech astronomer Mike Brown. "I could probably see about two times further with no light pollution. It puts a big damper on what we can find."
Billboards, Dealerships
Some Inland billboards and car dealerships are among the key sources of light pollution, using bright white or unshielded lights, said John Garrett, an amateur astronomer in Wildomar, who is helping Palomar push for a tougher ordinance.
Garrett said more businesses need to be encouraged to use low-pressure sodium lights and shields that focus the light more narrowly. Unlike white lights, low-pressure sodium lights emit a narrow band of light that astronomers can filter out.
County officials said some businesses don't like the yellowish tinge of low-pressure sodium lights because they wash out colors, making outdoor displays unattractive. And some law enforcement officials worry that not enough light could compromise the public's safety.
Riverside County Planning Department officials will review proposals to amend the light-pollution ordinance soon, said Mark Balys, the county's deputy planner. But before any changes are made, the business community and law enforcement will have to be consulted, he said.
New Discoveries
Since its first telescope was installed in 1936, the Palomar Observatory has become world-renowned, the source of a wide range of astronomical studies, including the hunt for asteroids that might threaten Earth and probes of distant galaxies.
Last year, with the aid of a Palomar telescope, Brown discovered an object larger than Pluto in the Kuiper Belt, a group of icy bodies orbiting the sun beyond Neptune.
The discovery, which landed Brown in Time magazine as one of the 100 most influential people, sparked a frenzied debate by the International Astronomical Union over whether Pluto ought to be reclassified, with other Kuiper Belt objects, as a dwarf planet. In August, the union voted to demote Pluto.
On a recent visit to Palomar, Phil Nicholson, an astronomy professor at Cornell University, and J.J. Kavelaars, an astronomer at the Herzberg Institute of Astrophysics near Victoria, British Columbia, were looking to make history themselves, capturing images of five faint objects in the Kuiper Belt.
But light pollution affected the quality of the images, Nicholson said.
Ten years ago, he could photograph the objects using 400- to 500-second exposures. Today, he has to limit it to 300-second exposures because longer exposures would capture too much of the bright background caused by light pollution.
Nicholson said he worries that Palomar Observatory might suffer the same fate as the Mount Wilson Observatory in Los Angeles. In the mid-1980s, the observatory stopped studying faraway galaxies in favor of closer, brighter stars because light pollution had become so bad.
After Palomar, the nearest major observatories for Southern California astronomers are the Kitt Peak National Observatory west of Tucson, Ariz., and the Mauna Kea Observatory in Hawaii, said Scott Kardel, Palomar spokesman.
Light pollution doesn't only affect astronomers, it affects anyone who wants to enjoy the night sky, said Karl Dunscombe, a Palomar telescope operator for 10 years.
He remembers the awesome splendor of the night sky when he bought a cabin in the area 18 years ago. That magic is gone, Dunscombe said.
"Do we want to explain the Milky Way to our kids through a virtual image or let them go out and see it for themselves and spark that interest?" he said.
Tougher Ordinance
As part of a presentation he gave to Riverside County planning officials earlier this year, Garrett showed pictures of some businesses he thought used excessive lighting.
One of them was the Denny's restaurant in Temecula, which, Garrett said, uses 14 high-intensity, wide-angle floodlights to illuminate its roof.
There's no reason to light up the roof "unless you expect customers to land on the roof," he said.
Debbie Atkins, a Denny's spokeswoman, said the lights help draw attention to the business, which is open 24 hours. It also enhances safety and security, she said.
Car dealerships could play a big role in curbing light pollution if they were persuaded to use more low-pressure sodium lights, Garrett said
Peter Hoffman, director of the California Motor Car Dealers Association, said dealerships use white lights to make car displays more visible and more attractive. However, many dealerships use low-pressure sodium lights to illuminate their storage lots, he said.
Fears that less-invasive lights will compromise public safety and be too expensive for municipalities to install are overblown, said representatives of the International Dark-Sky Association, an Arizona-based organization that advocates for less light pollution.
It's a myth that brighter lights or more lights will make an area safer, said Lee Karalis, the association's spokeswoman.
Too much light can blind people and create shadows, she said. Good quality lights that minimize glare also save energy, Karalis said.
Municipal Ordinances
Several Riverside County municipalities have adopted their own light-pollution ordinances, stretching from the Coachella Valley to Temecula.
Last year, the Beaumont City Council adopted new rules that force businesses to point lights downward and restrict to 20 feet the height of light poles.
Laverne Booth, 72, an amateur astronomer in Hesperia who successfully petitioned San Bernardino County in 2003 to adopt an ordinance restricting outdoor lighting in all mountain and desert communities, said more awareness is needed.
"We need a star-filled night sky. It's part of our heritage," she said. "It's so inspiring to see that beautiful sky."
