How far do you have to drive to escape light pollution?
The honest answer is: it depends which direction you drive, not just how far. A city's glow does not spread evenly. One road out of town can reach a dark sky in twenty minutes. Another road, same distance, stays lit up for an hour.
Distance alone is the wrong unit. What actually matters is which darkness band you reach — and that depends on your city's shape and the terrain around it, not on a rule of thumb written for someone else's geography.
The six darkness bands
Star Ninja's map colors every spot on Earth by measured sky brightness, in six named bands:
- Very dark sky — up to 0.25 nW/cm²/sr
- Dark sky — up to 1 nW/cm²/sr
- Rural — up to 3 nW/cm²/sr
- Suburban — up to 10 nW/cm²/sr
- Bright suburban / urban fringe — up to 30 nW/cm²/sr
- Urban / heavily light-polluted — above 30 nW/cm²/sr
Higher numbers mean more artificial light reaching the sky, and fewer stars you can see. "Very dark sky" is where the Milky Way shows clearly. "Urban" is a city center, where only the brightest planets and stars cut through.
These are approximate radiance bands, not a Bortle or SQM class. They come from measured satellite data, not a guess.
An honest distance method
Set a start point on the map — your home, or wherever you're leaving from. Click any spot you're considering. The panel shows two numbers: the straight-line distance in kilometers, and an approximate drive figure.
The approximate drive figure is a straight-line distance divided by a flat 70 km/h. It is not a routed estimate — no roads, no traffic, no turns. Treat it as a rough guide, and check a real map before you commit to a route.
What to do next
There's no shortcut that skips your own geography. The map on Star Ninja lets you set a start point, click candidate spots in every direction, and compare their darkness bands and distances side by side. That comparison is the answer — not a single number that assumes a city like yours.
Open the map and try a few directions out of your own town. If you want a walkthrough of what each reading on the panel means, see how to read the dark-sky map.