YozoraAtlas

How dark is the sky in Pays de la Loire?

Sky darkness for 7 towns and parks in Pays de la Loire, 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 Cholet (20.33, Bortle 5), the brightest Nantes (19.07, Bortle 6). Milky Way season in Pays de la Loire runs May to July: on moonless nights the bright core stands clear of the horizon, climbing to about 14° 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 Pays de la Loire with every place marked

Darkest skies in Pays de la Loire

  1. CholetBortle 520.33
  2. LavalBortle 520.03
  3. La Roche-sur-YonBortle 520.01

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 Pays de la Loire

  1. NantesBortle 619.07
  2. AngersBortle 619.44
  3. Le MansBortle 619.47
  4. Saint-NazaireBortle 519.78

All 7 places in Pays de la Loire

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Angers6Cholet5La Roche-sur-Yon5Laval5Le Mans6Nantes6Saint-Nazaire5