Live network median
—mag/arcsec²
Waiting for current station readings
The whole reserve
The network at a glance
Network typical sky
—mag/arcsec²
Median of every site's typical night
Sites online
—sensors
Darkest site
—
Bortle 1–3 sites
—
Sites reaching genuinely dark-sky classes
Nights recorded
—site-nights
Across the whole network
Datapoints stored
—readings
Individual sensor readings in the network archive
Brightest site
—
Where we watch
The station map
Sedan is the first connected station. Sites 2–20 will appear here as their SQMs come online. Adelaide is included as an illustrative typical city comparison, not a live tracking station. Higher values mean darker skies. Click Sedan to visit its site.
BrighterDarker
Station reading
Adelaide · typical 18.0
Map data © OpenStreetMap contributors
Sensor network
Visit a station
Site 1 at Sedan is connected now. Sites 2–20 are coming soon and will receive their own dashboards as readings begin.
The long view
The reserve through the seasons
Each dot is the network median across all reporting sites for one night — using only moon-free readings so moonlight does not distort the public trend.
Insights from the network
Understand the numbers
How dark is dark?
Magnitudes per square arc-second
Our sensors measure the brightness of the night sky in magnitudes per square arc-second (mag/arcsec²) — the standard unit used by astronomers. It runs backwards from what you might expect: bigger number = darker sky.
The scale is logarithmic: every 5 magnitudes is a 100× difference in light. So a sky at 22 mag/arcsec² isn't a little darker than an 18 mag/arcsec² city sky — it's about 40 times darker.
The Bortle scale
The Bortle scale describes what you can actually see, from Class 1 (the darkest skies on Earth) to Class 9 (inner-city). The badges show how many of our sites reach each class.
About
The River Murray International Dark Sky Reserve
Covering more than 3,200 km² of South Australia's Mid Murray region — from Bow Hill to Blanchetown along the river, and west to the foothills of the Mount Lofty Ranges — the River Murray International Dark Sky Reserve was Australia's first, accredited by the International Dark-Sky Association in October 2019. Its core at Meldanda, near Cambrai, records skies that regularly reach Bortle Class 1–2: nights so dark the Milky Way casts a shadow.
Project Nightwatch turns the reserve's scientific monitoring into something everyone can explore. Unihedron Sky Quality Meters measure the glow of the night sky every minute, while infrared cloud sensors track conditions overhead. And the long game matters: the night sky brightens by up to a magnitude around solar maximum, so the reserve is building an 11-year dataset across a full solar cycle. The district's best reading — 21.96 mag/arcsec², recorded near Swan Reach in 2016/17 — shows what solar-minimum skies can do.
The technical-preview network reads the SQM-LE TCP protocol through Google Cloud-routed station endpoints. Each station endpoint can be replaced independently as physical Unihedron equipment comes online. Following standard practice in light-pollution research, readings above 22.0 mag/arcsec² are excluded as likely dark-cloud or obstruction artefacts. Rankings, Bortle classes and long-term trends also require the Sun to be at least 12° below the horizon and the Moon to be below the horizon or less than 25% illuminated. All other readings remain available in station detail and protected raw feeds. Sky brightness readings are zenith measurements in mag/arcsec²; timestamps in charts are local time (UTC+10:30).