This guide to dark sky lighting for residential and commercial properties is a great resource for anyone looking for particulars on how to turn their property lighting into a dark-sky friendly environment. It’s actually part of the Outdoor Lighting Ordinance in Shorewood Hills of Wisconsin, but it has some very useful information.

First, they cover off the importance of having dark sky ordinances:

 

  • To improve safety, security, and visibility.
  • To eliminate the effects of harsh, glaring lights on the nighttime skies and the wildlife living all around us.
  • To limit light trespass into other people’s property.

 

Then, the article goes into some specifics about how the average person can achieve dark-sky compliant lighting outdoors to assist with the outdoor lighting ordinance:

Examples of Dark Sky Lighting Fixtures Do's and Don't'sUse properly shielded light fixtures

Shields help to direct the light properly so that it illuminates only what you wish to see. Shields most often are non-adjustable enclosures affixed to lights that aim the light downward. They even provide a handy diagram to demonstrate when lights are properly shielded, and when they need to be changed.

For this community’s outdoor lighting ordinance, they even provide requirements for the amount of shielding required for each fixture, depending on the wattage of the bulb. For residents, any lights with 150 watts must be fully shielded (no light is allowed to shine above the horizontal plane) and those that are 60 watts must be partially shielded so that less than 2 percent of the light shines above the horizontal plane. Very specific!

Lighting curfews

Another interesting aspect to this outdoor lighting ordinance are the curfews applied to residential lighting systems, requiring that all lighting be turned off by 10 pm! This even includes holiday and decorative lighting. (Commercial lighting systems must be turned off or dimmed 50 percent by 11 pm). That’s a great way to encourage people to save money and the environment!

Light limits

Residents are also encouraged to limit the amount of light they have on their properties. For instance, they cannot produce more than 7,000 lumens or 400 watts of light at any one time.

 

In addition to all of these guidelines, the article outlines a few ways to figure out whether you’ve got too-bright lights and how to fix the problem. Like I said, a great little resource!