# Bortle Scale Light Pollution Map

> A Bortle Scale map helps people interpret night-sky darkness from class 1 dark skies to class 9 inner-city skies.

Light Pollution Map displays Bortle-style classes as a quick reference for observing quality. The Bortle Scale is useful because it translates sky brightness into a human-readable level, but it should be treated as a guide rather than a precise physical measurement.

## Bortle Class Summary

- Class 1-2: excellent dark skies; the Milky Way can be highly detailed.
- Class 3-4: rural to rural/suburban transition; Milky Way visibility is still plausible.
- Class 5-6: suburban skies; fainter Milky Way detail is strongly reduced.
- Class 7-9: urban skies; most faint stars and the Milky Way are lost.

## How To Use It

Use Bortle class for a first-pass comparison, then check SQM, artificial brightness ratio, moon phase, cloud cover, and local horizon conditions before planning an observation or imaging session.

## Related URLs

- Map: https://lightpollutionmap.app/
- Full AI reference: https://lightpollutionmap.app/llms-full.txt
- Bortle Scale reference: https://en.wikipedia.org/wiki/Bortle_scale