YozoraAtlas

How dark is the sky in North Holland?

Sky darkness for 10 towns and parks in North Holland, 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 Den Helder (20.03, Bortle 5), the brightest Amsterdam (18.48, Bortle 7). The bright core of the Milky Way never climbs clear of the horizon haze anywhere in North Holland 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 Holland with every place marked

Darkest skies in North Holland

  1. Den HelderBortle 520.03
  2. Zuid-Kennemerland National ParkBortle 519.69
  3. HoornBortle 519.61

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 Holland

  1. AmsterdamBortle 718.48
  2. HoofddorpBortle 618.98
  3. HaarlemBortle 619.15
  4. IJmuidenBortle 619.27
  5. HilversumBortle 619.38

All 10 places in North Holland

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Alkmaar6Amsterdam7Den Helder5Haarlem6Hilversum6Hoofddorp6Hoorn5IJmuiden6Purmerend6Zuid-Kennemerland National Park5