Light Pollution Map

What is Light Pollution Map

Light Pollution Map is a web-based light pollution map that turns satellite-derived night-light data into an interactive sky-brightness view. The main interaction is simple: click a point on the map and it shows the Bortle class for that location along with an approximate SQM reading. That makes it useful as a dark sky map, a light pollution checker, and a quick way to compare urban glow against rural observing sites.

The app’s own wording emphasizes two things: it is global, and it is location-specific. Instead of only showing broad regional averages, it lets you inspect a precise point and see how bright the sky is likely to be there. The map also includes a more classic light-pollution intensity view based on VIIRS satellite data.

Key features

• Interactive map lookup for any point you click.
• Bortle Scale ratings from 1 to 9, from very dark skies to heavily light-polluted city skies.
• Approximate SQM values, which provide a more technical sky-quality reading in magnitudes per square arcsecond.
• A VIIRS-based light pollution intensity view, labeled as a classic map mode.
• Search support for locations, including broad regions and specific cities.
• Dark-sky planning help for stargazing, Milky Way viewing, meteor showers, and aurora spotting.

The app is designed to answer practical questions quickly, such as “what Bortle class am I in?” and “where are the darkest skies near me?” It also highlights that skyglow can extend far beyond city limits, so a spot that looks distant on a road map may still be affected by nearby illumination.

How to use it

1. Open the map in your browser.
2. Search for a place or pan to the area you want to inspect.
3. Click anywhere on the map to view the Bortle class and approximate SQM value for that point.
4. Compare several nearby locations to find the darkest option.
5. Use the result to choose a viewing site for stargazing or night photography.

If you are planning a trip, the map works best as a pre-check tool. You can compare a city edge, a rural stop, and a darker outlying area before you drive. The app also suggests that Bortle 1–2 locations are the closest thing to genuinely dark, unpolluted skies.

For Milky Way viewing, the map’s guidance points toward places that are Bortle 4 or darker, especially when paired with a new moon. For astrophotography, a brighter reading can help you decide whether to shorten sub-exposures before you head out.

Who it is for

This light pollution map is useful for people who need a quick, visual way to judge observing conditions.

• Amateur astronomers comparing sites for visual observing.
• Astrophotographers who need a starting point for exposure planning.
• Hikers and campers looking for dark-sky destinations.
• Meteor-shower watchers who want darker horizons away from city glow.
• Aurora chasers who want to combine sky darkness with a forecast layer.
• Anyone trying to understand the brightness of their local night sky.

It is especially helpful if you want a plain-English view of sky quality without needing to own a handheld darkness meter. The Bortle class and SQM estimates make the results easier to interpret than raw satellite imagery alone.

What to know before you use it

Light Pollution Map is a practical estimate tool, not a replacement for on-site measurements. The SQM value shown on the map is approximate, and the Bortle rating is derived from satellite data rather than a physical meter reading taken at the exact spot.

A few limitations matter:

• True zero-light-pollution locations are rare, even in remote areas.
• Skyglow can travel over 100 km from a city, so distance alone does not guarantee darkness.
• The map does not measure weather, humidity, haze, moon phase, or local cloud cover, all of which can change what you see.
• For official observing conditions, park status, or local restrictions, use the site of the observatory, park, or dark-sky reserve you plan to visit.

The tool is best used as a planning layer before a trip, not as the only source for a final go/no-go decision. If you need exact SQM readings for research, fieldwork, or documentation, confirm them with a physical meter on site. For broad trip planning, though, this dark sky finder gives a fast and useful first pass. Light Pollution Map is most valuable when you use it to narrow down a shortlist of observing sites before checking current conditions elsewhere.