DarkSkyNZ’s measurements are in magnitude per square arc seconds (mpsas) in line with the established protocol for measuring celestial magnitudes, darker the sky, higher the mpsas reading.
Tekapo, located within the Aoraki Mckenzie Dark Sky Reserve, one of 11 internationally certified dark sky reserves, enjoys night sky brightness ranging from 21.5 mpsas to 21.7 mpsas.
DarkSkyNZ noted in Auckland, a difference of close to 5 magnitudes (21+ mpsas to 16+ mpsas) between locations in Waiheke Island and the bright locations in CBD when measured on the same night and under the same conditions. This showed that the city night sky (one could only see very few bright celestial objects) is 100 times brighter than the Waiheke Island night skies with a multitude of stars and the dwarf galaxies, Large Magellanic Cloud and Small Magellanice Cloud visible to the naked eye.
DarkSkyNZ’s measurements for Aotea/Great Barrier Island averaged 27.9 mpsas (see Map below for details) and were instrumental in the island being accredited as the 3rd International Dark Sky Sanctuary on 7 June 2017.
The article Quantifying Night Sky Brightness Discovers Pristine Night Skies in Auckland provides more details on these as a case study.