How dark is the sky in Luxembourg?
Sky darkness for 6 towns and parks in Luxembourg, worked out from NASA satellite images of light at night (2025). 4 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Upper Sûre Natural Park (21.18, Bortle 4), the brightest Luxembourg (18.79, Bortle 7).
19
Bortle class, 1 pristine to 9 city center
park or dark-sky place
city
Numbers like 21.95 or 16.97 are the brightness of the sky overhead on a clear, moonless night, in mag/arcsec². The scale runs backwards: a lower number means a brighter sky, from about 22 for a natural sky to about 17 in a city center.
How the readings are made
Darkest skies in Luxembourg
- Upper Sûre Natural ParkWiltz · Bortle 421.18
- Our Nature ParkClervaux · Bortle 421.14
- PutscheidClervaux · Bortle 421.14
- Mëllerdall Nature ParkEchternach · Bortle 420.82
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.
Brightest city skies in Luxembourg
Darkest place in each canton of Luxembourg
| Canton | Places | Dark places Bortle 1 to 4 | Darkest place |
|---|---|---|---|
| Clervaux | 2 places | 2 dark | Our Nature Park21.14 · Bortle 4 |
| Echternach | 1 place | 1 dark | Mëllerdall Nature Park20.82 · Bortle 4 |
| Esch-sur-Alzette | 1 place | 0 dark | Esch-sur-Alzette19.37 · Bortle 6 |
| Luxembourg | 1 place | 0 dark | Luxembourg18.79 · Bortle 7 |
| Wiltz | 1 place | 1 dark | Upper Sûre Natural Park21.18 · Bortle 4 |