Temecula Valley Astronomers - Light Pollution

Light Pollution in the Temecula Valley

Fri, 27 Apr 2007 12:49:12 -0700

Riverside county is is experiencing rapid growth that threatens to pollute the night sky with a glow of man-made light. Most light pollution is an unnecessary by-product of poorly designed light fixtures that also waste energy, create visibility hazards, and can be considered intrusive. Failure to design for the effect of Riverside County's growth on the night time environment will affect communities, observatories, parks, and wilderness areas. While many of the effects are merely unpleasant or nuisances, some have safety ramifications and threaten scientific research at Palomar Observatory.

In this section, I plan to show the good and bad examples of lighting from this valley. I will be adding examples of lighting for business and institutions as well as for residential safety and decorative use. I welcome suggestions.

John Garrett

Examples:
Temecula, Denny's Restarant (bad lighting example)
Temecula, Rancho Ford (good lighting example)
Glaring Floodlights(a bad lighting example)

Light Pollution documents

Fri, 26 Jan 2007 12:27:07 -0800

Below are documents created to raise awares of night lighting issues. To view the larger files, it is highly recommended that you right-click the link and choose download, rather than try to view the files online.

Glaring Floodlights

Fri, 27 Apr 2007 12:47:00 -0700

Much light pollution would be eliminated merely be ensuring that lights do their job well. For example, the purpose of the flood lighting shown below is to protect property or provide visibility. But it does either of these poorly.

First, whether it protects the driveway or vehicles parked there from theft or vandalism is debatable (I have numerous examples of theft and vandalism occuring in the presence of flood lighting). And second, it creates enough glare to be a nuisance and safety hazard, which undermines its benefit. Note that the light is cast upward and outward as well as downward. Lighting the trees across the street provides no deterence to theft or vandalism, and is a waste of energy. But more relevent to a residential neighborhood with children, it creates glare that can impair a motorist's ability to see a rock in the street or a child on foot, on a skateboard, or on a bike. Cameras tolerate glare better than the human eye, so the following photos will show objects clearly, but use the next two photos in sequence to get an idea of how your vision would respond to the sudden appearance of the light from behind the tree.

Visibility is good here for both the camera and the eye, because the tree effectively sheilds the light. But as soon as you drive out of the shadow of the tree, the light is like a stab in the eyes.

At this point, the motorist's eyes are adapting to the brightest light -- the flood light. The pupils are contracting and the faint light from pedestrians is overwhelmed by the glare. This is similar to the approach of another car's headlights. The difference here it that lights like this become permanent fixtures, always interfering with seeing. I know of numerous intersections where left and right turns are hazardous because there is always an unshielded light in the way of the where I need to look to make a safe turn. The solution is simple. Shield the light with a viser so that it lights only the driveway and sidewalk. This shielding would allow the light to perform its function without the nuisance and hazard of glare, which in turn reduces light pollution.

Rancho Ford, A step in the right direction

Fri, 26 Jan 2007 12:27:54 -0800

I was pleased last year to notice that Rancho Ford started using low pressure sodium (LPS) lights in their service area after closing. In this picture, you can see a difference in light pollution between their LPS lights and a nearby lot with all white light.

A close-up shows there is no loss in ability to see:

A close-up of the other lot shows how much white light is reflecting upward from a typical car lot. Notice the color of the grass appears white:

Business Lighting: Best lit roof in town!

Fri, 26 Jan 2007 12:29:28 -0800

I'm being sarcastic in the title. Lighting a roof arguably has little value in providing safety and security. In the case of Denny's in Temecula, their roof lighting is excessive.

The photograph below shows the Denny's in Temecula and their roof lights. Each light puts out a wide beam. Denny's uses 14 of these wide-angle, high intensity floodlights. On the far right, you can see the flare from one of these lights. Considering that the photograph is taken on an embankment above the building and off to the side by about 45 degrees, you can appreciate the wide field of these lights. Much of the light being used misses the roof and creates glare and light pollution instead.

A business has every right to use light for safety and security and to attract customers. Safety and security comes from pointing lights downward so motorists and pedestrians can come and go without interfering glare. Attracting customers can be achieved by lighting a sign; Denny’s has lit signs on their roof as well as a lit sign on a pole (not shown). These signs are more courteous and effective at welcoming customers than shining floodlights skyward. The latter mostly obscures the stars from us who enjoy the night sky or who conduct research at our nearby observatory.

The second best-lit roof award goes to Norm Reeves Honda. No matter how bright they make the light shown in this picture, it will still be dark under that canopy: