YozoraAtlas

How dark is the sky in Wallonia?

Sky darkness for 10 towns and parks in Wallonia, worked out from NASA satellite images of light at night (2025). 2 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Entre-Sambre-et-Meuse National Park (21.23, Bortle 4), the brightest Liège (19.07, Bortle 6). The bright core of the Milky Way never climbs clear of the horizon haze anywhere in Wallonia while the sky is fully dark; the rest of the band passes overhead, with the longest moonless nights from September to April.

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

NASA satellite night-lights map of Wallonia with every place marked

Darkest skies in Wallonia

  1. Entre-Sambre-et-Meuse National ParkBortle 421.23
  2. Deux Ourthes Nature ParkBortle 421.16

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 Wallonia

  1. LiègeBortle 619.07
  2. CharleroiBortle 619.09
  3. MouscronBortle 619.11
  4. La LouvièreBortle 619.24
  5. MonsBortle 619.28

All 10 places in Wallonia

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Charleroi6Deux Ourthes Nature Park4Entre-Sambre-et-Meuse National Park4La Louvière6Liège6Mons6Mouscron6Namur5Tournai6Verviers5