How dark is the sky in Andalusia?
Sky darkness for 49 towns and parks in Andalusia, worked out from NASA satellite images of light at night (2025). 23 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Sierras de Cazorla, Segura y Las Villas Natural Park (21.61, Bortle 4), the brightest Seville (17.91, Bortle 8). Milky Way season in Andalusia runs March to September: on moonless nights the bright core stands clear of the horizon, climbing to about 25° 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 Andalusia
- Sierras de Cazorla, Segura y Las Villas Natural ParkBortle 421.61
- Sierra de Castril Natural ParkBortle 421.57
- Sierra de Andújar Natural ParkBortle 421.56
- the Andalusian Sierra MorenaBortle 421.54
- Sierra de Cardeña y Montoro Natural ParkBortle 421.47
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.