Table 1 Color levels used in the maps.

The first column gives the ratio between the artificial brightness and the natural background sky brightness (assumed to be 174 μcd/m2); the second column gives the artificial brightness (μcd/m2); the third column gives the approximate (that is, assuming a natural background of 22 mag/arcsec2) total brightness (mcd/m2); and the fourth and fifth columns give the colors.

Ratio to natural brightnessArtificial brightness (μcd/m2)Approximate total brightness (mcd/m2)Color
<0.01<1.74<0.176Black
0.01–0.021.74–3.480.176–0.177Dark gray
0.02–0.043.48–6.960.177–0.181Gray
0.04–0.086.96–13.90.181–0.188Dark blue
0.08–0.1613.9–27.80.188–0.202Blue
0.16–0.3227.8–55.70.202–0.230Light blue
0.32–0.6455.7–1110.230–0.285Dark green
0.64–1.28111–2230.285–0.397Green
1.28–2.56223–4450.397–0.619Yellow
2.56–5.12445–8900.619–1.065Orange
5.12–10.2890–17801.07–1.96Red
10.2–20.51780–35601.96–3.74Magenta
20.5–413560–71303.74–7.30Pink
>41>7130>7.30White