Find a darker sky
Town lights wash out the stars. Peabody guesses how bright your sky is at home, how many stars you might count on a clear night with no Moon, and which way to drive to find a darker sky.
Five kinds of night sky
| City sky | About 70 stars: the Moon, the planets and only the brightest stars; most star patterns are missing pieces. |
|---|---|
| Bright sky | About 300 stars: the bright stars and the main shapes of the easiest star patterns, like the Big Dipper and Orion. |
| Suburb sky | About 650 stars: all the star patterns, and the Milky Way faint or hidden. |
| Country sky | About 1,500 stars: the Milky Way across the sky in summer and autumn, and more stars than you can count. |
| Dark sky | About 2,000 stars: the Milky Way bright and full of shape, and thousands of stars. |
How to find a darker spot
- Turn off the lights you can: porch, yard and the room behind you. Stand where a wall or a tree hides the streetlights.
- Give your eyes 20 minutes with no screens. A red light keeps your night eyes; Sky Tonight has a red Outside mode.
- Look away from town. The sky is brightest over the nearest city, so face the other way.
- With a grown-up, try a park, a field, a beach or a lake shore with a wide-open sky, ideally the way the guess says gets darker.
- Go when the Moon is a thin crescent or not up: a bright Moon hides faint stars as much as a town does.
How the guess is made
It isn't a measurement. We added up the light of every town within about 150 miles, using where people lived in the 2010 Census and a rule astronomers call Walker's law (a town's glow fades with distance, faster than you might think), then turned that into how faint a star you can see and how many stars that means. Places that shield their lights, like dark-sky towns, are darker than the guess; places near big stadiums, factories or highways can be brighter. Your ZIP stays on this device: the page asks only for the file that covers your whole 300-mile sky area. More in our guide to light pollution and how dark is dark enough.
“Owls see well in the dark. So do you, after twenty minutes away from bright lights.”