How dark is the sky in Australia?
Sky darkness for 223 towns and parks in Australia, worked out from NASA satellite images of light at night (2025). 152 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Sturt National Park (21.95, Bortle 2), the brightest Melbourne (17.37, 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 Australia
- Sturt National ParkNew South Wales · Bortle 221.95
- Dulcie Range National ParkNorthern Territory · Bortle 221.95
- Garig Gunak Barlu National ParkNorthern Territory · Bortle 221.95
- Judbarra / Gregory National ParkNorthern Territory · Bortle 221.95
- Karlu KarluNorthern Territory · Bortle 221.95
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 Australia
| State | Places | Dark places Bortle 1 to 4 | Darkest place |
|---|---|---|---|
| Australian Capital Territory | 2 places | 1 dark | Namadgi National Park21.63 · Bortle 4 |
| New South Wales | 68 places | 43 dark | Sturt National Park21.95 · Bortle 2 |
| Northern Territory | 20 places | 16 dark | Dulcie Range National Park21.95 · Bortle 2 |
| Queensland | 41 places | 28 dark | Alton National Park21.95 · Bortle 2 |
| South Australia | 14 places | 9 dark | Gawler Ranges National Park21.95 · Bortle 2 |
| Tasmania | 17 places | 13 dark | Mount William National Park21.94 · Bortle 2 |
| Victoria | 19 places | 8 dark | Croajingolong National Park21.94 · Bortle 2 |
| Western Australia | 42 places | 34 dark | Cape Arid National Park21.95 · Bortle 2 |