YozoraAtlas

How dark is the sky in Østfold?

Sky darkness for 4 towns and parks in Østfold, worked out from NASA satellite images of light at night (2025). None of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Halden (18.74, Bortle 7), the brightest Fredrikstad (18.42, Bortle 7). The bright core of the Milky Way never climbs clear of the horizon haze anywhere in Østfold while the sky is fully dark; the rest of the band passes overhead, with the longest moonless nights from October 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 Østfold with every place marked

Darkest skies in Østfold

  1. HaldenBortle 718.74
  2. MossBortle 718.61
  3. SarpsborgBortle 718.45

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 Østfold

  1. FredrikstadBortle 718.42

All 4 places in Østfold

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Fredrikstad7Halden7Moss7Sarpsborg7