YozoraAtlas

How dark is the sky in Bragança?

Sky darkness for 3 towns and parks in Bragança, worked out from NASA satellite images of light at night (2025). 2 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is International Douro Natural Park (21.41, Bortle 4), the brightest Bragança (19.52, Bortle 5). Milky Way season in Bragança runs April to August: on moonless nights the bright core stands clear of the horizon, climbing to about 20° 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 Bragança with every place marked

Darkest skies in Bragança

  1. International Douro Natural ParkBortle 421.41
  2. Montesinho Natural ParkBortle 421.34

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 Bragança

  1. BragançaBortle 519.52

All 3 places in Bragança

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Bragança5International Douro Natural Park4Montesinho Natural Park4