The map displays VIIRS/World Atlas/Clouds/Aurora/IAU observatories and the user SQM measurements overlay over Microsoft Bing base layers (road and hybrid Bing maps). The primary use is to show VIIRS/DMSP data in a friendly manner, but over time it also included some other interesting overlays that concern light pollution like SQM/SQC, World Atlas 2015 zenith brightness, clouds, aurora and IAU observatories. If you have a permanent SQM reader installed you can add it to the map by sending me an e-mail. If you want an analysis of radiance (VIIRS/DMSP) changes over a period of time, then please use the Lighttrends application (look under Help). Please send comments and requests for new features via email (look under help) Functionalities: - VIIRS, Sky Brightness (World Atlas 2015), Cloud coverage and Aurora forecast layers - VIIRS and Sky Brightness layers can be displayed in color blind friendly colors - Road & Satellite base maps - Cloud animation for the last 12 hours - Get detail radiance and SQM values from layers at a click. For World Atlas 2015, you also get Bortle class estimation. - SQM, SQM-L, SQC, SQM-LE, SQM readings submitted by users - Submit your own SQM (L) readings - Observatories layer - Save your favorite locations - Distance measurement tool with azimuth angle report - Offline mode (Sky brightness map and a base map are saved to your device, so it will be displayed when you are offline)