Globe at Night - Sky Brightness Monitoring Network (GaN-MN)

The GaN-MN project, an extension of the original Globe at Night project, is a global night sky brightness monitoring network using a commercially available meter (SQM-LE by Unihedron) for long-term monitoring of the light pollution conditions in different places around the world.

The project aims to:

  1. deploy a standardized night sky measurement method for worldwide light pollution research;
  2. highlight the negative environmental impacts of abusive artificial lighting for the general public and policy makers; and
  3. sustain light pollution public education and promote public engagement by live worldwide night sky brightness data and night sky measuring programs.

About the GaN-MN Data

Globe at Night is hosting data taken by this network. It can be downloaded as a CSV file that can be opened in any spreadsheet application. The file has the following headers:

unique ID for each data entry
timestamp according to the server clock
timestamp converted to UTC
timestamp corrected to local time
serial number of SQM-LE
nsb, sensor_frequency, sensor_period_count, sensor_period_second, temperature:
raw data reported by the unit, where nsb: reading in magnitudes per square arc second, see section 8.6 of the manual
code of monitoring station (location of SQM-LE), complete list

Download the GaN-MN Data







  1. Data are released on a monthly basis. For example, the CSV file of January 2015 contains the raw data collected from 00:00:00 January 1st, 2015 to 23:59:59 January 31st, 2015 UTC and sorted by the received_utc.
  2. The GAN-MN data is posted by six months after it has been collected. Data collected in January will be posted six months later, in July.
  3. The data is posted as CSV files that may be opened in a spreadsheet or a text editor.
  4. Data released are provisional as there is only limited quality check. Please contact GaN-MN ( for details.