How dark is the sky in Estonia?
Sky darkness for 15 towns and parks in Estonia, worked out from NASA satellite images of light at night (2025). 10 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Matsalu National Park (21.74, Bortle 3), the brightest Tallinn (17.41, Bortle 8).
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 Estonia
- Matsalu National ParkLääne County · Bortle 321.74
- Karula National ParkVõru County · Bortle 321.70
- Soomaa National ParkPärnu County · Bortle 421.64
- Haanja Nature ParkVõru County · Bortle 421.57
- Alutaguse National ParkIda-Viru County · Bortle 421.50
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 county of Estonia
| County | Places | Dark places Bortle 1 to 4 | Darkest place |
|---|---|---|---|
| Harju County | 3 places | 2 dark | Lahemaa National Park21.40 · Bortle 4 |
| Ida-Viru County | 3 places | 1 dark | Alutaguse National Park21.50 · Bortle 4 |
| Lääne County | 1 place | 1 dark | Matsalu National Park21.74 · Bortle 3 |
| Pärnu County | 2 places | 1 dark | Soomaa National Park21.64 · Bortle 4 |
| Tartu County | 2 places | 1 dark | Vooremaa Nature Park21.06 · Bortle 4 |
| Valga County | 1 place | 1 dark | Otepää Nature Park21.26 · Bortle 4 |
| Võru County | 3 places | 3 dark | Karula National Park21.70 · Bortle 3 |