The light pollution map has two base layers (road and hybrid Bing maps), VIIRS/World Atlas/Clouds/Aurora overlays and a point feature overlay (SQM, SQC and Observatories).
If you want detailed analysis of radiance (VIIRS/DMSP) changes over a period of time, then please use the Lighttrends web application
(not mobile optimised).
For more information view the help
Send comments about the app and request new features to Jurij Stare