Dark Sky & Light Pollution Map
See where artificial light drowns out the night sky, then click any point, search a place or use your location to get an estimated Bortle class, naked-eye limiting magnitude, and what that means for aurora, the Milky Way core and deep-sky objects.
Dark Sky & Light Pollution Map
Loading night-lights map and Bortle estimator
Basemap: OpenStreetMap contributors. Light layer: NASA GIBS VIIRS Black Marble night-lights imagery (a satellite proxy for artificial light, not a sky quality measurement).
The Bortle scale
The Bortle Dark-Sky Scale rates night-sky darkness from class 1 (pristine) to class 9 (inner city). The naked-eye limiting magnitude (NELM) is the faintest star you can see without optical aid; ranges below are the standard published values.
| Class | Sky | NELM |
|---|---|---|
| 1 | Excellent dark-sky site | 7.6-8.0 |
| 2 | Typical truly dark site | 7.1-7.5 |
| 3 | Rural sky | 6.6-7.0 |
| 4 | Rural/suburban transition | 6.1-6.5 |
| 5 | Suburban sky | 5.6-6.0 |
| 6 | Bright suburban sky | 5.1-5.5 |
| 7 | Suburban/urban transition | 4.6-5.0 |
| 8 | City sky | 4.1-4.5 |
| 9 | Inner-city sky | 4.0 or brighter-sky limit |
Dark skies help, but the aurora also needs geomagnetic activity. Check the live aurora map and Sky Tonight before you drive out.