Bright light has long troubled astronomers, who generally shy away from deep sky observing under full Moon skies. The natural light from a bright Moon floods the sky and hides the Milky Way, dim galaxies and nebula, and shooting stars. In recent years, human-made light pollution has dramatically surpassed the interference of even a bright full Moon. Bright white LED streetlights, while often more efficient and long-lasting, create unexpected problems for communities replacing their older streetlamps. Some notable concerns are increased glare and light trespass, less restful sleep, and disturbed nocturnal wildlife patterns. Awareness is increasing about how much light is too much light at night. Individuals can join efforts to measure it and even reduce the effects of light pollution locally.
Amateur astronomers and citizen scientists around the globe are invited to participate in the Globe at Night (GaN) program to measure light pollution. GaN volunteers take measurements a few scheduled days every month and submit them to a database using methods ranging from low-tech naked-eye observations to high-tech sensors and smartphone apps. These are compiled into a comprehensive map of light pollution and its change over time.
DarkSky International has other resources for getting involved. It has long been a proponent of smart lighting design and policy. Their website provides resources for amateur astronomers and like-minded people to help communities understand the negative impacts of light pollution and how smart lighting policies can bring the stars back to their night skies and make their streets safer by reducing glare. “Smarter, not brighter” lighting choices can save considerable sums of money with shielded, directional lighting, motion detectors, timers, and even choosing the proper warmer “temperature” of new LEDs.
The DarkSky International has notably helped usher in “Dark Sky Places”, areas around the world that are protected from light pollution. Moab, Castle Valley, and parks in the area are already Dark Sky Places and contribute to providing residents and visitors with incredible views of the Milky Way just outside town—perfect places to spot the wonders of a meteor shower.
Before and after pictures of replacement lighting at the 6th Street Bridge over the Los Angeles River. The second picture shows light is not directed to the sides and upwards from the upgraded fixtures, reducing skyglow. However, it also shows the use of brighter, whiter LEDs along with increased light bounce back from the road. Image Credit: The City of Los Angeles
Light pollution has been visible from space for a long time, but new LED lights are bright enough that they stand out from older streetlights. Astronaut Samantha Cristoforetti took the above photo from the ISS cupola in 2015. The newly installed white LED lights in the center of the city of Milan are noticeably brighter than the lights in the surrounding neighborhoods. Image Credit: NASA/ESA
