A 1–9 rating of how dark a night sky really is. StellarSpot uses Bortle class as the primary darkness rating for every stargazing destination. Lower is darker — and better. Tap a class below to see what you'd actually see.
How dark is dark?
A 1–9 rating of how dark a night sky really is — from a pristine wilderness sky where the Milky Way casts a shadow, to a city sky where only the Moon and a few bright stars break through. Lower is darker is better. Tap a level to see what you’d actually see.
Scale devised by John E. Bortle, Sky & Telescope (2001). Magnitude and SQM figures are approximate — Bortle class, naked-eye limiting magnitude, and Sky Quality Meter readings don’t map one-to-one, and SQM becomes less reliable in brighter skies.
Every class from the darkest wilderness sky to a downtown city sky, with what you can actually see and where you find each level.
The sky is almost overwhelming. The Milky Way is bright enough to cast a faint shadow, and you can spot the zodiacal light and natural airglow. Thousands of stars are visible at once.
The Triangulum Galaxy (M33) is easy to see with the naked eye, and the summer Milky Way looks like veined marble. Faint airglow hugs the horizon; clouds show up as dark holes in the stars.
The Milky Way still looks complex and detailed. Several star clusters are naked-eye objects, and only a little glow shows low on the horizon. For most people this is where the sky becomes genuinely spectacular.
Domes of light glow over distant towns. The Milky Way overhead is still impressive but loses its fine detail. M33 becomes a tricky, look-slightly-to-the-side object.
The Milky Way is faint and washed out, and disappears near the horizon. Light sources glow in most directions. You can still see plenty of stars, but the sky no longer feels dark.
The Milky Way is only a hint near straight-up, if you can find it at all. The sky glows grayish. The Andromeda Galaxy shows only as a modest smudge.
The whole sky glows grayish-white. The Milky Way is invisible. Only the brighter stars and the planets show through the light pollution.
The sky glows orange-white — bright enough to read a headline. Only bright stars and the outlines of familiar constellations appear, and even those are missing stars.
The entire sky is lit, even straight overhead. Only the Moon, the planets, and the very brightest stars and clusters (like the Pleiades) break through — perhaps a few dozen stars in all.