How dark is the sky in Austria?
Sky darkness for 33 towns and parks in Austria, worked out from NASA satellite images of light at night (2025). 19 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Salzburger Lungau and Kärntner Nockberge Biosphere Reserve (21.75, Bortle 3), the brightest Vienna (18.57, Bortle 7).
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 Austria
- Salzburger Lungau and Kärntner Nockberge Biosphere ReserveCarinthia · Bortle 321.75
- Riedingtal Nature ParkSalzburg · Bortle 321.72
- Hohe Tauern National ParkSalzburg · Bortle 321.70
- Gesäuse National ParkStyria · Bortle 421.69
- the EisenwurzenLower Austria · Bortle 421.68
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.
Darkest place in each state of Austria
| State | Places | Dark places Bortle 1 to 4 | Darkest place |
|---|---|---|---|
| Burgenland | 2 places | 2 dark | Raab-Őrség-Goričko Nature Park21.51 · Bortle 4 |
| Carinthia | 4 places | 2 dark | Salzburger Lungau and Kärntner Nockberge Biosphere Reserve21.75 · Bortle 3 |
| Lower Austria | 12 places | 9 dark | the Eisenwurzen21.68 · Bortle 4 |
| Salzburg | 4 places | 3 dark | Riedingtal Nature Park21.72 · Bortle 3 |
| Styria | 2 places | 1 dark | Gesäuse National Park21.69 · Bortle 4 |
| Tyrol | 1 place | 0 dark | Innsbruck19.54 · Bortle 5 |
| Upper Austria | 4 places | 2 dark | Kalkalpen National Park21.66 · Bortle 4 |
| Vienna | 1 place | 0 dark | Vienna18.57 · Bortle 7 |
| Vorarlberg | 3 places | 0 dark | Feldkirch20.30 · Bortle 5 |