comments

Dark sky at night, an astronomer's delight

By: Gus Thomson, Journal Staff Writer
-A +A
George Robinson muses that most people are too busy inside their homes watching TV to worry about it. But as an amateur astronomer living in the foothills, Robinson is involved in a pursuit that depends on keeping the encroachment of light from all its many sources at bay in the heavens. Uncovered light sources combine to gang up on the darkness, lighting up particles like dust in the atmosphere and turning the inky night into a filmy haze. That results in little chance for astronomers and the casual naked-eye observer to see all that the night sky has to offer, Robinson said. Globally, the International Dark-Sky Association works to protect and preserve the nighttime environment and a heritage of dark skies ? mostly through advocating quality lighting that doesn?t escape upward and outward. Robinson said he?s been to communities like Phoenix, Ariz., where he?s been forced to go 50 miles outside to find a viewable area. ?The sky is just obliterated,? Robinson said. And he?s talked to a visitor from New York City who had never really seen the stars the way you can when the sky is a jet-black projector of the cosmos. After 32 years in Auburn, Robinson said that Auburn has been losing its darkness. ?But we?re not in too bad a situation,? Robinson said. ?It?s the old story ? ?We could be better but we could also be a whole lot worse.?? For outdoor lighting, the Dark-Sky Association recommends a ?dark-sky friendly? lighting design that includes provisions to not over-illuminate an area. Turning off lights when not needed is another plank in the platform to preserve the darkness. And the association recommends shielding landscape and security lighting so the majority of beams hit a target and don?t cause glare spreading to normal viewing angles. Will Wong, Auburn community development director, said that while there are no lighting standards in the city?s zoning ordinance, it?s standard to add a condition of approval during the design review process requiring shielding on lights to keep glare from spreading to adjoining properties. ?It?s easy to add shields,? Wong said. At Placer County, Loren Clark, assistant director of the Community Development Resource Agency, said dark skies have been brought up from time to time during the development of some projects. But nothing has triggered a drive to establish engrained standards. Instead, issues to do with lighting are dealt with on a case-by-case basis, he said. In Arizona, at least one community has recently tackled a potential dark-skies provision. The town of Wickenburg drafted an ordinance that would allow older developments to retain their lighting but required new development to keep from lighting the sky. The prospect of darkness in more rural areas of Placer County at higher elevations has attracted two well-known astronomy experts. Don Machholz in Colfax, has discovered 11 comets using high powered binoculars and telescopes. Tony Hallas, considered one of the best astrophotographers in the world, has made his home in the Foresthill area for the past 10 years. Both said they moved to comparatively lightless areas from urban regions that had been overtaken by light pollution. Hallas and his wife, Daphne?s, photos have been published in Smithsonian Magazine, National Geographic and Geo Magazine. Tony writes a monthly column for Astronomy Magazine on imaging. Hallas said his earliest astronomy efforts took place at 3,600 feet on Mount Pinos, between Ventura and Kern counties in Southern California. But growth of light in the night sky had turned a pitch-black canvas for photography many nights into a murky gray panorama, with light glowing upward and outward from the Los Angeles and Bakersfield regions. It was time to leave in 2000 and Hallas made the move to Foresthill after exploring up and down the foothills to find treeless property that could hold a backyard observatory. ?We found a lot with very few trees in the Foresthill area,? Hallas said. ?It was cheap because nobody wanted it without trees.? From his backyard observatory, even without the telescope, Hallas can see the Milky Way and the Andromeda Galaxy with the naked eye. ?You don?t get that in Auburn,? Hallas said. ?But if you just get to the Foresthill Bridge, just out of the city lights, you do.? Machholz moved two decades ago from the San Jose area because of encroaching light pollution and has since made most of his discoveries from his Colfax observatory. But he?s also had to deal with light pollution at a local level, fighting a losing battle in an attempt to convince a billboard company to aim their lights on four signs in Colfax downward instead of upward. Two weeks from now, he?ll be in Auburn at Overlook Park to host a ?star party? to observe a total lunar eclipse. Even there, it?s a struggle, with lights from the parking lot forcing the observation into the unlighted outskirts of the park. Machholz said that because of a brightening sky to the south and west in areas like Roseville and Sacramento, he?ll generally train his telescope on the eastern night sky. But now, even there, Machholz is finding a new potential threat to the darkness. ?There?s an increase of light pollution from the Tahoe area to the east,? Machholz said. ----------------------------------------------- Fast facts: Light pollution - Lighted towers and tall buildings can confuse migrating and local birds. Some collide with other birds or structures ? or circle the lights until they die of exhaustion. - Night lighting that increases sky glow around sports stadiums has been found to stop the mating activity of nearby frogs. - Humans can be affected by what is called sky glow and light trespass. Health researchers have established that exposure to artificial light at night reduces the human body?s production of melatonin. Higher levels of melatonin slow growth of breast cancer tumors in women and may similarly affect other cancers, including prostate cancer. Source: International Dark-Sky Association