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Dark Skies & Light Pollution

Understand · Protect · Restore the Night

The stars haven't gone anywhere. We've just turned up the lights.

Light pollution is one of the fastest-growing forms of pollution on Earth, and one of the easiest to reverse. Here is how it works, why the night matters, and what every home, venue and community can do.

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What Is Light Pollution?

Artificial light at night that shines where it isn't needed or wanted

Light pollution is excessive or misdirected artificial light that brightens the night sky, hides the stars, and spills into places it was never meant to go.

Most of it comes from ordinary outdoor lighting: streetlights, parking lots, sports fields, signs, and bare "dusk-to-dawn" fixtures on homes and barns. Light that escapes upward or sideways scatters in the atmosphere and returns as a glowing dome over every town.

Unlike most pollution, it disappears the moment a light is redirected, dimmed or switched off.

An orange dome of skyglow over city lights at night, with only a few stars visible

Skyglow

The brightening of the night sky over populated areas. It can be seen from many miles away, and it is why most people can no longer see the Milky Way from home.

Glare

Excessive brightness that causes visual discomfort and makes the darkness around it harder to see into, especially for older eyes and for drivers.

Light Trespass

Light falling where it isn't intended or needed, such as a neighbor's floodlight shining across the property line and into a bedroom window.

Clutter

Bright, confusing groupings of light sources, common along commercial strips, that add glare and distraction.

Wasted Light

Light that goes up into the sky or beyond its target does nothing useful, yet it still costs energy and money.

Lost Darkness

Birds, insects, fireflies and people all evolved with dark nights. Artificial light at night disrupts their natural rhythms.

See It for Yourself

Shield, dim and warm the lights of a mountain valley and watch the stars return

The same mountain valley at night: with typical lighting about 300 stars are visible, with dark-sky-friendly lighting about 1,700
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Five Principles for Responsible Outdoor Lighting

From DarkSky International and the Illuminating Engineering Society: light where you need it, when you need it, and no more.

1 · Useful

Every light should have a clear purpose. If it doesn't, switch it off.

2 · Targeted

Fully shielded fixtures aimed down, so light lands only where it is needed.

3 · Low Level

No brighter than the task requires. Over-lighting adds glare.

4 · Controlled

Timers, dimmers and motion sensors keep light off when no one needs it.

5 · Warm-Colored

Warm light around 2700 K or lower; limit blue-rich white light.

Why the Night Matters

Darkness is a natural resource for wildlife, for our health, and for wonder

For nearly all of human history, every child grew up beneath a sky full of stars. Today most of us never see the Milky Way from home.

Artificial light at night disorients migrating birds, draws moths and other pollinators away from their work, and drowns out the flashes fireflies use to find each other. In people, bright and blue-rich light at night can disrupt sleep and the circadian rhythms that regulate our health.

The Milky Way rising over dark mountains while a town's light dome glows on the horizon
80%+

of the world's population, and over 99% of people in the US and Europe, live under light-polluted skies. (Falchi et al., 2016)

~80%

of North Americans can no longer see the Milky Way from where they live, according to the same world atlas of night sky brightness.

9.6%/yr

How fast the night sky brightened from 2011 to 2022, from more than 50,000 citizen-science star counts. (Kyba et al., 2023)

30%+

of US outdoor lighting is wasted, mostly by unshielded fixtures, according to DarkSky International.

Wildlife

Light at night disorients migrating birds and interferes with moths, pollinators and fireflies.

Health

Bright, blue-rich light at night can disrupt sleep and the body's daily rhythms.

Dark Skies Near Asheville

Where to experience a natural night sky in Western North Carolina

PARI

The Pisgah Astronomical Research Institute near Rosman, a former NASA tracking station, is a certified International Dark Sky Park with public astronomy programs.

Mayland Earth to Sky Park

In Burnsville, Mayland Community College's park and Bare Dark Sky Observatory form a certified International Dark Sky Park, the first in the Southeast.

Blue Ridge Parkway

Overlooks such as Tanbark Ridge (Milepost 376.7), Stony Bald (402.6) and the Mount Pisgah area (407.6) open wide views away from city lights. Check the National Park Service road status first.

Stargazing in Asheville

Dark Sky Education & Consulting

Dark sky science, advocacy, and preservation

Stephan Martin is a sought-after speaker on dark sky science and advocacy: why mitigating the effects of light pollution and preserving dark skies matters for human health, the natural world, and the future of the planet.

He offers light pollution education and consulting, and stargazing experiences that reveal what a dark night sky holds.

Stephan Martin presenting on dark sky preservation in Saba, West Indies
Dark Sky Consulting Lighting Self-Check

Light Pollution Questions

Short answers to common questions

What causes light pollution?

Mostly outdoor lighting that is unshielded, poorly aimed, brighter than needed, left on when no one needs it, or rich in blue light. Light that escapes upward or sideways scatters in the atmosphere and creates skyglow, while poorly aimed fixtures cause glare and light trespass.

How can I reduce light pollution at home?

Follow the five principles: switch off lights you don't need, use fully shielded fixtures aimed downward, use the lowest brightness that does the job, add timers or motion sensors, and choose warm-colored bulbs of about 2700 K or lower. The dark-sky-friendly lighting guide has a checklist.

Are LED lights bad for the night sky?

Not necessarily. LEDs are efficient and easy to dim and control. The problems come from blue-rich, overly bright and unshielded LED fixtures. Warm-colored, fully shielded, dimmable LEDs can be among the most night-sky-friendly choices.

What is the Bortle scale?

A nine-level scale created by amateur astronomer John Bortle to describe how dark the night sky is, from Class 1, an excellent dark-sky site, to Class 9, an inner-city sky where only the brightest stars and planets can be seen. The simulator estimates a Bortle class as you change the lighting.

Where can I find dark skies near Asheville?

The two certified International Dark Sky Parks nearby are the Pisgah Astronomical Research Institute (PARI) near Rosman and Mayland Earth to Sky Park in Burnsville. Higher Blue Ridge Parkway overlooks away from towns also offer good views when the Parkway is open.

Does Stephan offer dark sky presentations and consulting?

Yes. Stephan offers light pollution education and consulting and is a sought-after speaker on dark sky science and advocacy. See dark sky consulting, or use the contact form below.