Free Software:
Zone Calculator
Zone Calculator is a free program that converts a sky brightness value to the zone color defined in The New World Atlas of Artificial Sky Brightness (2016, Falchi et al). It can convert values among several units of measure: magnitude per square arcsecond, naked eye limiting magnitude, and millicandelas per square meter.
It requires no installation - just download, save to disk and run it. Zone Calculator is compatible with Windows 7, 8 and 10, including high resolution displays.
Zone colors are calculated and displayed in SQM Reader Pro.
