How dark is the sky in Galicia?
Sky darkness for 11 towns and parks in Galicia, worked out from NASA satellite images of light at night (2025). 4 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is O Invernadeiro Natural Park (21.53, Bortle 4), the brightest Vigo (18.50, Bortle 7). Milky Way season in Galicia runs April to August: on moonless nights the bright core stands clear of the horizon, climbing to about 19° at its highest.
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
Darkest skies in Galicia
- O Invernadeiro Natural ParkBortle 421.53
- Baixa Limia e Serra do Xurés Natural ParkBortle 421.08
- Dunas de Corrubedo and Lagoas de Carregal e Vixán Natural ParkBortle 420.62
- Fragas do Eume Natural 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.