Dark-sky map and night-sky brightness

A free light-pollution map that shows how bright the night sky is across the world. The coloured overlay reveals where city glow drowns out the stars and where the sky is still dark, and you can tap any point for its exact zenith brightness in mag/arcsec² — with a plain-language sky rating and whether the Milky Way is visible there. It is the quick way to find the darkest skies near you for stargazing or astrophotography.

How to use the light pollution map

1
Read the overlay

Green areas are dark skies; yellow, orange and red are increasingly light-polluted. Use the slider to fade the overlay against the map.

2
Tap a spot

Click anywhere to get the exact zenith sky brightness in mag/arcsec², a sky rating and whether the Milky Way is visible there.

3
Find dark skies

Pan out from the city and look for the green zones — those are your best bets for stargazing and astrophotography.

4
Check near you

Press “Near me” to read the sky brightness at your own location.

Find dark skies and check the sky brightness anywhere

Overlay
Tap the map to read the sky brightness
Sky brightness
darklit up

Light-pollution data: Falchi et al., world atlas by D. Lorenz (from VIIRS), free to use with attribution. The atlas deliberately does not give an exact Bortle class. Map © OpenStreetMap & CARTO.

What makes it special

A world light-pollution overlay built from VIIRS satellite data, with an opacity slider
Tap anywhere for the exact zenith sky brightness in mag/arcsec², decoded from the atlas
A plain-language sky rating and whether the Milky Way is visible at that spot
A “near me” button to check the sky right where you are
Honest about scales — it leads with mag/arcsec² and shows Bortle only as a rough reference
Served through our own servers so it loads reliably, even where the source site is blocked

Frequently asked questions

What does mag/arcsec² mean?

It is a measure of how bright the night sky is — magnitudes per square arcsecond. Higher numbers mean a darker sky: a pristine site reads about 22.0, a rural sky around 21.5, the suburbs near 20, and an inner city under 18. It is the same scale a sky-quality meter (SQM) uses.

Why don’t you show an exact Bortle class?

The atlas author asks specifically not to, because the Bortle scale describes the whole visible sky and your local horizon, while this map measures only the zenith brightness — the two do not map onto each other exactly. We show mag/arcsec² as the real number and a rough Bortle only as a familiar reference.

How current is the data?

The map is an annual atlas built from VIIRS satellite imagery, not a live feed. Light pollution changes slowly from year to year, so it is an accurate guide for planning, but it does not reflect tonight’s conditions like weather or a bright Moon.

Will I really see the Milky Way there?

The Milky Way starts to show once the sky is darker than about mag 21, and is obvious from truly dark sites. The tool flags this from the brightness, but you also need a clear, moonless night and time for your eyes to adapt to the dark.

Where does the data come from?

From the world atlas of artificial night-sky brightness by Fabio Falchi and colleagues, made interactive by David Lorenz from VIIRS satellite data. We serve the tiles and brightness values through our own servers so the map works reliably and loads quickly.

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Who is this tool for?
🎓 Students 📚 Educators & Teachers 📷 Photographers
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