How dark is the sky in Canterbury?
Sky darkness for 11 towns and parks in Canterbury, 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 Aoraki Mackenzie (21.91, Bortle 2), the brightest Christchurch (18.26, Bortle 8). Milky Way season in Canterbury runs February to October: on moonless nights the bright core stands clear of the horizon, climbing to about 77° 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 Canterbury
- Aoraki MackenzieBortle 221.91
- KaikōuraBortle 221.91
- Arthur's Pass National ParkBortle 221.90
- Aoraki / Mount Cook National ParkBortle 321.88
- Oxford Forest Conservation AreaBortle 321.73
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.