YozoraAtlas

How dark is the sky in Cantabria?

Sky darkness for 5 towns and parks in Cantabria, worked out from NASA satellite images of light at night (2025). 3 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Saja-Besaya Natural Park (21.32, Bortle 4), the brightest Torrelavega (18.77, Bortle 7). Milky Way season in Cantabria runs April to August: on moonless nights the bright core stands clear of the horizon, climbing to about 18° at its highest.

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 Cantabria with every place marked

Darkest skies in Cantabria

  1. Saja-Besaya Natural ParkBortle 421.32
  2. Collados del Asón Natural ParkBortle 421.18
  3. Oyambre Natural ParkBortle 420.96

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 Cantabria

  1. TorrelavegaBortle 718.77
  2. SantanderBortle 718.85

All 5 places in Cantabria

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Collados del Asón Natural Park4Oyambre Natural Park4Saja-Besaya Natural Park4Santander7Torrelavega7