Community Standards for Reporting Skyglow Observations

The introduction of the SQM and the IYA Lightmeter have led to a large number of permanent skyglow monitoring stations coming online. At the same time, a number of individuals and groups have developed their own non-commercial devices (e.g. NSBM from the IDA, and DigiLum from Henk Spoelstra). While these developments are excellent news for those interested in monitoring light pollution, there exists no common standard for recording measurements from the devices.  This has greatly hampered efforts to compare measurements from different locations, and to develop databases containing long term measurements from around the world.

At the Cabauw Lightmeter InterComparison (CLIC) workshop in May 2012, a group of light pollution researchers defined a proposal for a new, standard format to be used for recording skyglow measurements. This proposal was shared with the light pollution community, has undergone several revisions, and will soon be finalized. The goal of the standardization is to make comparisons of future measurements easier, regardless of whether the measurements were taken by currently available detectors, or by new, future detectors. For this reason, the community has designed a format that hopefully anticipates the needs of potential future devices (e.g. multiple channels with different filters or opening angles), but without making the format so open as to not actually be helpful.

After a four month period of public comment, the new standard was officially adopted at the 12th European Symposium for the Protection of the Night Sky. Although the public commenting phase is officially over, if you notice something in the format or documentation that should be changed, please contact Christopher Kyba (christopher.kyba at

The format has been endorsed by Unihedron (makers of the SQM) and by the makers of the SQM Reader program. Both companies have pledged to release new versions of the readout code that conform to the community standard once it is finalized.

The format is explained in detail here

Example files for the SQM device is here and for the or IYA Lightmeter device here.