Sky brightness
Zenith photometer, magnitudes per square arcsecond. The series most often pulled for light-pollution work in Fennoscandia.
series id sqm-zenith
Archive updated continuously · last block 24 Aug 2026
Twenty-one years of uninterrupted sky.
Northbridge runs an unattended measurement station above the Arctic Circle. Temperature, pressure, humidity, sky brightness and radio noise are sampled every second and published as open time series — no registration, no scraping limits.
CC BY 4.0 · cite as Northbridge Observatory, series ID and block range
21 yearscontinuous record
1 Hzbase sampling rate
14.6 TBarchive served in July
7instruments online
Instruments and series
Radio noise floor
Broadband monitor, 20–1500 MHz, one sweep per second. Raw sweeps are kept, not just the aggregates.
series id rf-floor
Surface weather
Temperature, pressure, relative humidity, wind. Redundant sensors, disagreement flagged rather than silently averaged.
series id surface
Seeing monitor
Differential image motion, reported when the sky is clear enough to solve. Gaps are explicit; we never interpolate them away.
series id dimm
Data access
Series are served as compressed blocks. A block is one instrument over one UTC day; large pulls are just many blocks, and resuming a partial transfer is supported.
GET /data/series/download?series=rf-floor&from=2026-08-01&to=2026-08-24&format=parquet
# whole-year pull, resumable
curl -C - -O "https://northbridge-observatory.org/data/series/download?series=surface&year=2025"Parquet, NetCDF and plain CSV are produced from the same source blocks, so checksums stay comparable across formats. Mirrors are welcome — the archive is designed to be copied in full.
The station
The site sits on a granite outcrop at 480 m, chosen in 2005 for its low horizon and distance from town lighting. It runs unattended for most of the year; a maintenance visit happens each September before the dark season.
Power comes from the regional grid with a battery bridge sized for 40 hours. When the bridge runs out the station shuts down cleanly and marks the gap — an honest hole in the record is worth more than fabricated continuity.
Status
| Archive delivery | Operational |
| Ingest from station | Operational |
| Format conversion | Operational |
| Seeing monitor | Clouded out |
Last gap: 2 July, 41 minutes, grid maintenance. Marked in every affected series.