Conserving our Dark Skies

By Pierre Martin

Over the years, the universe and its treasures as seen from our planet, have been slowly fading away. Today, the sight of myriads of stars and brilliant Milky Way is virtually unknown to most people. Why? City development and poor outdoor lighting solutions are the main culprits. They prevent us from seeing what the real night sky looks like. This ever growing problem has been referred by astronomers as light pollution.

The growing problem of light pollution

Our ancestors were used to looking a pitch black sky and seeing a brilliant glowing Milky Way overhead on most clear moonless nights. Most of all the urban development began near the dawn of the twentieth century. Many new advances and innovations in technology suddenly appeared. With it, populations in cities around the world augmented rapidly into larger urban centers. Naturally, it became necessary to increasingly light up everything as much as possible. Today, very few, if any truly dark sky locations remain in eastern North America. Even the few remaining isolated pristine skies are being invaded by the glow of distant cities. A city (like Ottawa) will produce a noticeable glowing "dome" in the sky even from 60 kilometers or more away. Why is so much light permitted to be wasted up in the sky?

Cheap, inefficient lamp fixtures can be seen everywhere in and out of town. The most common model widely in use for street and highway lighting is the "cobra head" style fixture. It is often claimed that they are cheap to buy and that they do the job. Yet, these fixtures are a throwback to 1960s technology, a time when light pollution was a barely known issue. The "Cobra heads" have a poor overall illumination as they waste a large percentage of light horizontally. They can be seen as bright, glaring point sources even from large distances. They probably contribute to most of the overhead city sky glow, since they are used in such large quantities. If taxpayers were more sensitized to this situation, they probably would not allow so much money to be wasted by sending light in the wrong direction. Other poor lighting comes from billboard signs, buildings and houses. The "globe" style lights in cities are good at lighting the entire sky but only some parts on the ground. The so-called "security" lights are also a big problem. Automobile dealers are especially eager to light up their lot in an excessive way. They too often mount overly bright fixtures that will uselessly spill half of their useful light straight up. If these lights are not properly shielded, the glare they create will make harsh shadows. Intruders actually love hiding in harsh shadows. Deep in the country, many farmers install blinding and glaring "security" lights for their properties. This is all appealing to a potential intruder.

What to do to combat light pollution? To get a shotgun and blow up the darn things to smithereens is NOT the solution. The goal is certainly not to return to the dark ages. What we can do is encourage proper lighting methods for our city. Commercial lighting manufacturers offer sharp full-cutoff fixtures that directs all the light where it is most needed; on the ground. With this in mind, they not only use less wattage than traditional fixtures, but also give a more evenly quality lighting of the ground. These lights come in all varieties and shapes for different purposes. Full-cutoff lights also improve safety by cutting glare for motorists. Good quality lighting will not only help darken the skies, but will give the public a better quality of life and be much more cost efficient in the long run.

Fortunately, we are seeing an increasing trend of full-cutoff lights installed in several new communities of the Ottawa region. Several Shopping centers, schools and many business among others are doing the same thing for their properties. This is an encouraging sign, but still much work needs to be done before our night skies begin to show any improvement. The lights already in place must be either changed, or outfitted with an add-on reflecting shield that will redirect the light properly.

More coming soon

In the near future, I will have photos on this page to demonstrate different examples of good and bad lighting in the Ottawa valley. I will illustrate how much this problem is creeping up into our dark skies.