For most people today, the night sky is never truly dark. Artificial light from cities, roads and buildings spreads into the atmosphere as a glow that hides faint stars and the Milky Way. For night photographers, finding dark skies is often more important than any camera setting. This lesson explains light pollution, how darkness is measured, how to find and plan dark locations, and what you can do when perfect darkness is not available.
What is light pollution?
Light pollution is excessive or misdirected artificial light at night. The part that affects photographers most is skyglow: a brightening of the night sky caused by light scattering in the atmosphere. It reduces contrast between stars and the sky, hides the Milky Way and adds orange or green-gray gradients to photos, especially near the horizon. Other forms include glare and light trespass from nearby lamps.
The Bortle scale
The Bortle scale rates how dark a night sky is, from 1 (the darkest) to 9 (inner city).
| Class | Sky type | What you can expect |
|---|---|---|
| 1–2 | Excellent, truly dark sites | Milky Way casts faint shadows; countless stars; very remote areas |
| 3 | Rural sky | Milky Way very clear; slight glow near the horizon |
| 4 | Rural/suburban transition | Milky Way visible but less detailed; glow from towns |
| 5–6 | Suburban | Milky Way faint or barely visible |
| 7–9 | City | Only the brightest stars and planets |
Tip:For Milky Way photography, aim for Bortle 4 or darker where possible. Light pollution maps, often color-coded by Bortle class or sky brightness, help you find these places.
Planning a dark-sky location
- Check a light pollution map for dark areas within reach.
- Look for dark-sky parks and reserves: some areas are officially recognised for protecting night skies.
- Check direction: make sure the direction you will photograph, such as toward the Milky Way core, is away from the nearest city glow.
- Check access and safety: roads, permission, terrain and phone coverage.
- Scout in daylight for compositions and safe paths, as in night landscapes.
- Combine with moon and weather planning from Milky Way and star photography.
Warning:Remote dark locations can be dangerous at night. Never go alone without telling someone your plans, and follow the safety advice in wildlife and remote-location safety.
Other things that brighten the sky
- Moonlight: even a dark site looks bright under a full moon.
- Twilight: true darkness begins some time after sunset, after astronomical twilight ends.
- Haze, dust and humidity: scatter light and reduce clarity.
- Altitude: higher locations often have clearer air above much of the haze.
Reducing light pollution effects
| Approach | How it helps | Limits |
|---|---|---|
| Point away from city glow | Avoids the brightest gradients | Restricts composition |
| Shoot later at night | Some lights switch off; city glow may reduce | Depends on the area |
| Correct white balance and gradients in editing | Removes orange casts and uneven sky | Cannot recover stars hidden by glow |
| Stacking | Improves faint detail by reducing noise | Does not remove skyglow itself, as in astrophotography workflow and stacking |
| Light-pollution filters | Block some wavelengths from certain lamps | Less effective with modern broad-spectrum LED lighting; can add color casts |
Protecting dark skies
Dark skies are a shared natural resource, important for wildlife, human health and our connection to the night. Photographers can help by using red light, avoiding unnecessary bright lights at dark sites, following park rules and supporting local dark-sky efforts. Dark-sky etiquette was introduced in night landscapes.
Common mistakes
- Choosing a dark site but pointing toward a city: bright gradients ruin the sky.
- Forgetting the moon: a dark site under a full moon is not dark.
- Shooting before astronomical twilight ends: the sky is still too bright.
- Expecting filters to remove modern LED glow: results are limited.
How professionals plan
Night photographers combine light pollution maps, moon phase calendars, weather and cloud forecasts and core-position planning apps. They build lists of dark locations, know which directions are clean, and travel to remote dark-sky areas for important work. When darkness is limited, they adapt composition and processing rather than forcing a weak result.
Practical examples
A city glow problem
- Situation
- Your Milky Way photo from a rural site has a strong orange glow at the bottom.
- What to do
- You check a light pollution map and find a town in that direction, then move 30 km further away and face the other way.
- Why it works
- Skyglow is strongest toward towns and near the horizon.
- Result
- A much cleaner sky with a clearer Milky Way.
Planning a desert trip
- Situation
- You want to photograph the Milky Way during a desert trip.
- What to do
- You pick a Bortle 2 area on a light pollution map, schedule the trip near the new moon in peak season and scout compositions in daylight.
- Why it works
- Darkness, timing and preparation work together.
- Result
- A brilliant, detailed Milky Way over the dunes.
Key points
- Light pollution, especially skyglow, hides stars and adds colored gradients.
- The Bortle scale rates darkness from 1 (darkest) to 9 (city); aim for 4 or darker for the Milky Way.
- Use light pollution maps, dark-sky parks, direction checks and daylight scouting.
- Moon, twilight, haze and altitude also affect sky darkness.
- Reduce effects by direction, timing, editing and stacking; help protect dark skies.
Frequently asked questions
What is the Bortle scale?
How do I find dark skies near me?
Do light pollution filters work?
When does the sky become fully dark?
Conclusion
Light pollution is the biggest obstacle in night photography. Learn the Bortle scale, use maps and planning tools, face away from glow, combine darkness with moon and weather planning and help protect the night sky. Next, you will learn the workflow for stacking astrophotography images.
Finished reading? Track your progress through Long exposure and night.