YozoraAtlas

How dark is the sky in North Rhine-Westphalia?

Sky darkness for 69 towns and parks in North Rhine-Westphalia, worked out from NASA satellite images of light at night (2025). 5 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Arnsberg Forest Nature Park (21.19, Bortle 4), the brightest Essen (18.71, Bortle 7). The bright core of the Milky Way never climbs clear of the horizon haze anywhere in North Rhine-Westphalia while the sky is fully dark; the rest of the band passes overhead, with the longest moonless nights from September to March.

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 North Rhine-Westphalia with every place marked

Darkest skies in North Rhine-Westphalia

  1. Arnsberg Forest Nature ParkBortle 421.19
  2. Teutoburg Forest/Egge Hills Nature ParkBortle 421.13
  3. Eifel National ParkBortle 420.95
  4. ArnsbergBortle 420.79
  5. Hohe Mark Nature ParkBortle 420.56

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 North Rhine-Westphalia

  1. EssenBortle 718.71
  2. DüsseldorfBortle 718.78
  3. LeverkusenBortle 718.90
  4. DortmundBortle 718.91
  5. KölnBortle 718.93

All 69 places in North Rhine-Westphalia

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Aachen6Ahlen5Arnsberg4Arnsberg Forest Nature Park4Bergheim5Bergisch Gladbach5Bielefeld5Bocholt5Bochum6Bonn6Castrop-Rauxel5Detmold5Dinslaken5Dormagen6Dorsten5Dortmund7Duisburg6Düren5Düsseldorf7Eifel National Park4Erftstadt5Essen7Euskirchen5Gladbeck6Grevenbroich5Gronau5Gummersbach5Gütersloh5Hagen5Hamm5Hattingen5Herford5Hohe Mark Nature Park4Hürth6Ibbenbueren5Iserlohn5Kerpen5Krefeld6Köln7Langenfeld6Leverkusen7Lippstadt5Lüdenscheid5Lünen5Marl6Menden5Minden5Moers6Mönchengladbach6Münster5Oberhausen6Paderborn5Pulheim5Ratingen6Recklinghausen5Rheine5Schwerte5Siegen5Solingen5Stolberg5Teutoburg Forest/Egge Hills Nature Park4Troisdorf6Unna5Velbert5Viersen5Wesel5Willich5Witten5Wuppertal5