YozoraAtlas

How dark is the sky in Plzeň Region?

Sky darkness for 6 towns and parks in Plzeň Region, 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 Šumava National Park (21.58, Bortle 4), the brightest Pilsen (18.68, Bortle 7). The bright core of the Milky Way never climbs clear of the horizon haze anywhere in Plzeň Region while the sky is fully dark; the rest of the band passes overhead, with the longest moonless nights from September to April.

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 Plzeň Region with every place marked

Darkest skies in Plzeň Region

  1. Šumava National ParkBortle 421.58
  2. Český les Protected Landscape AreaBortle 421.41
  3. the Manětín Dark Sky ParkBortle 421.38
  4. Brdy Protected Landscape AreaBortle 421.22

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 Plzeň Region

  1. PilsenBortle 718.68
  2. KlatovyBortle 519.99

All 6 places in Plzeň Region

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Brdy Protected Landscape Area4Klatovy5Pilsen7the Manětín Dark Sky Park4Český les Protected Landscape Area4Šumava National Park4