How dark is the sky in Central Sava?
Sky darkness for Trbovlje (20.56, Bortle 4), so far the only place in Central Sava on Yozora Atlas, worked out from NASA satellite images of light at night (2025). Milky Way season in Central Sava runs April to July: on moonless nights the bright core stands clear of the horizon, climbing to about 15° 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
Darkest skies in Central Sava
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.
All 1 place in Central Sava
Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.