City team plans a dark future for Toronto

A team of experts, hand-picked by city planning staff, is looking for ways to help Toronto see stars.

These astronomers, naturalists, technicians and businesspeople want to limit the excessive night time brightness of street lamps, buildings and outdoor lots. They know this as light pollution.

Light pollution’s harm is in the visible spectrum. The glare of city lights overwhelms the luminosity of stars, obscuring them from viewers on the ground.

Toronto lags more than a decade behind Richmond Hill, Ont., which passed a bylaw in 1995 to limit the effects of “sky glow,” thanks to a 23-year campaign by astronomer Tom Bolton, who studies massive stars with the huge reflector telescope at the David Dunlop Observatory.

Denis Grey, of the Royal Astronomical Society of Canada (RASC), applauds the Richmond Hill bylaw.

“You can actually see the Milky Way from Richmond Hill,” Grey said.

Despite the town’s policy, the haze of Toronto’s lights is visible from Richmond Hill, and even farther away.

Peter Hiscocks, who represents RASC on the Toronto committee, said that a colleague in Windsor, Ont., complains about Toronto’s light pollution.

“The whole golden horseshoe area is over-illuminated,” Hiscocks said.

Toronto apparently lacks two elements which paved the way to a bylaw in Richmond Hill: the world-class telescope at the David Dunlap Observatory, and Bolton, the astronomer who is renowned for his discovery of the first proven black hole.

“I think I had the advantage that I started the process right after I announced the discovery of the first black hole,” Bolton said, “which gave me a certain prestige with the local politicians. That gave me influence that I wouldn’t otherwise have had.”

Anti-light pollution activists claim its effects reach beyond the needs of sky-watchers. They warn that over-lit cities interfere with sleep thanks to “light trespass” into homes, which causes a variety of health problems. They also say it threatens road safety and wastes electricity.

Astronomers still lead the light pollution charge, however. Even the Toronto committee has at least five astronomers, including Bolton.

City environmental planner Kelly Snow, who formed the committee, says he would like to attract health professionals to the committee to discuss long-term bodily effects of light pollution, such as weakened immune systems. York University astronomer James Laframboise has examined health issues associated with the phenomenon, but there are no physicians at the table.

Toronto Hydro staff is a regular presence in the committee’s process, however.

The utility is working on a plan to replace the city’s 165,000 or so street lamps by about 2009. It is testing energy-efficient light sources and “full horizontal cut-off” fixtures which prevent light from spilling upward like shielded street lights used in Richmond Hill.

Snow has met with Toronto Hydro to harmonize the committee’s deadlines with the street-lamp initiative, called the Adaptive Lighting Asset Management Project (ALAMP)

“From our standpoint this is a major opportunity to put in fixtures that control light spill and light trespass in a more effective way,” Hiscocks said.

Lighting designer Gerry Cornwell consults with ALAMP. He oversees testing of numerous lamp designs in a west-Toronto testing yard and sits with the committee.

“I’m certainly interested, from a technical point of view, in what they’re doing, what they’re thinking of doing and what’s feasible,” Cornwell says.

What Cornwell decides is feasible may not satisfy everyone’s expectations.

Astronomers prefer narrow spectrum lights, such as the low-pressure sodium bulbs used in Richmond Hill. Sodium lights cast a yellowish glow which they say competes less with starlight, but is less attractive to citizens used to broader-spectrum white light.

“It has an impact on the appearance of buildings and landmarks,” Cornwell explained.

Hiscocks, an electrical engineer as well as an amateur astronomer, says he finds some discussions about light spectrum among committee members too technical.

“What astronomers would like is not necessarily what the public would like,” Hiscocks admitted.

“What we have to do is find a compromise that’s going to work for all of us,” Cornwell said.

Different trial models are expected leave Toronto Hydro’s lot for city streets for field testing phase of ALAMP by June.

About this article

By: Stephen Humphrey
Posted: Apr 17 2008 9:41 am
Filed under: Features News