How dark is the sky in Žilina Region?
Sky darkness for 10 towns and parks in Žilina Region, worked out from NASA satellite images of light at night (2025). 5 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is the Veľká Fatra Dark Sky Park (21.32, Bortle 4), the brightest Žilina (19.06, Bortle 6). Milky Way season in Žilina Region runs May to June: on moonless nights the bright core stands clear of the horizon, climbing to about 12° 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 Žilina Region
- the Veľká Fatra Dark Sky ParkBortle 421.32
- Tatra National Park (Slovakia)Bortle 421.27
- Malá Fatra National ParkBortle 421.14
- Horná Orava Protected Landscape AreaBortle 421.01
- Kysuce Protected Landscape AreaBortle 420.98
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.