Humans have inadvertently filled their towns and cities with outdoor lighting that generates a lot more light pollution than is necessary.
This costs communities their starry nighttime views. It also wastes electricity and hurts pollinators and other creatures.
But experts on reducing light pollution say good design is the solution. Outdoor lighting can work well for humans without spoiling night skies nearly so much as has become common today.
TAKE THE CABINS at Thousand Hills State Park near Kirksville, Missouri. Until recently, globe-shaped fixtures with bright white bulbs lit up each door.
That shape and color can backfire on people’s night vision, making it harder for their eyes to adjust and making shadows outside the cabins appear darker.
Park staff removed the globes and installed new fixtures that lie flush with the cabin awnings and contain amber bulbs.
That’s because effective outdoor fixtures light up the surfaces people need to see — in this case, the door and the ground just outside the cabin — without shining light directly into people’s eyes the way a globe does. Also, amber is a less jarring color for our eyes at night and it is less disruptive to wildlife.
Thousand Hills State Park is the twelfth Urban Night Sky Place in the world, certified by DarkSky International for its efforts.
Homeowners who would like to waste less energy and help the wildlife that lives in their neighborhoods can take a page out of the DarkSky movement’s book to reduce their own contributions to light pollution.
Use fixtures that restrict light to a downward angle
Picture a typical lamp post with a glass globe on top. It has two key flaws that waste energy and cause unnecessary skyglow and glare.
First, it allows light to shine upward, brightening the sky. Second, it releases much of its light horizontally, too, hitting the eyes of passersby.
The average neighborhood in Kansas and Missouri is full of street lights, garage lights, and other lights that make similar mistakes — sending light into the sky or into people’s eyes.
Dark-sky friendly fixtures make sure that light travels downward, says Vayujeet Gokhale, a physics and astronomy professor at Truman State University and a board member of DarkSky Missouri. This makes sure the fixture lights up the area you’re trying to see, while reducing glare and skyglow.
The Greater Big Bend International Dark Sky Reserve website features simple graphics and guidance to demonstrate how to improve outdoor lighting with fixtures that point light downward, among other changes.
If changing fixtures doesn’t fit into the household budget, Gokhale recommends choosing shielded fixtures the next time home repairs or renovations make the purchase of a new fixture necessary.
