Figures
Fig. 1 Upward emission functions used to compute the maps. The polar graph shows the three different light intensity distributions used to compute the three map versions: the Lambertian distribution with a peak toward the zenith (map A; blue), the function with peak intensity at low angles above the horizon plane (map B; green), and the function with peak at intermediate angles, 30° above the horizon plane (map C; yellow). The thick red line shows the overall best-fitting function.
Fig. 5 Maps of Europe’s artificial sky brightness, in twofold increasing steps, as a ratio to the natural sky brightness (assumed to be 174 μcd/m2). (A) The map shows the artificial sky brightness in V-band, as in the other maps. (B) The map shows the forecast of the perceived sky brightness for a dark-adapted eye after a transition toward 4000K CCT LED technology, without increasing the photopic flux of currently installed lamps. Table 1 indicates the meaning of each color level.
Fig. 9 Places on Earth farthest from pristine skies and unpolluted zenith skies. The sky brightness levels used here indicate the following: up to 1% above the natural light (0 to 1.7 μcd/m2; black); from 1 to 8% above the natural light (1.7 to 14 μcd/m2; blue); from 8 to 50% above natural nighttime brightness (14 to 87 μcd/m2; green); from 50% above natural to the level of light under which the Milky Way is no longer visible (87 to 688 μcd/m2; yellow); from Milky Way loss to estimated cone stimulation (688 to 3000 μcd/m2; red); and very high nighttime light intensities, with no dark adaption for human eyes (>3000 μcd/m2; white). The circles indicate the distance toward arriving at large territories (that is, very small islands, such as Ile d’Ouessant, France, are not considered here), toward a sky relatively unpolluted at the zenith (yellow circle), and toward a pristine sky (red circle).
Fig. 10 Map of light pollution’s visual impact on the night sky. The sky brightness levels are those used in the tables and indicate the following: up to 1% above the natural light (0 to 1.7 μcd/m2; black); from 1 to 8% above the natural light (1.7 to 14 μcd/m2; blue); from 8 to 50% above natural nighttime brightness (14 to 87 μcd/m2; green); from 50% above natural to the level of light under which the Milky Way is no longer visible (87 to 688 μcd/m2; yellow); from Milky Way loss to estimated cone stimulation (688 to 3000 μcd/m2; red); and very high nighttime light intensities, with no dark adaption for human eyes (>3000 μcd/m2; white).
Fig. 12 G20 countries sorted by polluted area. Countries of the G20 group whose area is polluted by the specified artificial sky brightness. Countries are ordered using the area of the three most polluted levels (that is, yellow, red, and white). Different orders may be obtained by choosing different pollution levels. Color ranges are shown on the right and indicate the pollution level (μcd/m2).
Fig. 16 Comparisons between sky brightness observations and atlas predictions. (Left) Contour plot comparing the weighted number of SQM observations to the predictions of the atlas in 0.1 magSQM/arcsec2 bins. The colors are scaled logarithmically relative to the peak: <0.7 weighted observations (blue), 0.7 to 5 weighted observations (green), 5 to 35.5 weighted observations (red), and 35.5 to 251 weighted observations (black). (Right) Fit residuals (observed minus predicted SQM values) for the complete data set, with a Gaussian fit. Negative values mean that the observer reported a sky brighter than the atlas predicted, whereas positive values mean that the observer reported a sky darker than predicted. The tail of brighter-than-predicted observations is usually either contaminated by nearby light sources or taken in different conditions than assumed (for example, unreported clouds, haze, or fog). The histogram shows the total number of observations, not weighted observations, so some locations contribute to multiple entries.
Fig. 17 Contour plots comparing the weighted number of SQM observations to the predictions of the atlas. The color scale is logarithmic and scaled relative to the peak value. Observations by citizen scientists tend to be slightly brighter than those made by professionals, with larger tails at very bright values, likely from observations taken too near lamps or under nonideal atmospheric conditions. GaN, Globe at Night; LotN, Loss of the Night app; RASC, Royal Astronomical Society of Canada; IDSP, International Dark Sky Places.
Fig. 18 Histograms showing the residuals (observed minus predicted SQM values) for the whole data set and for each of the different data providers. Negative values mean that the observer reported a sky brighter than the atlas predicted, whereas positive values mean that the observer reported a sky darker than predicted. The histograms show the total number of observations, not weighted observations, so some locations contribute to multiple entries. Superimposed are the best-fitting Gaussians.
Fig. 19 Comparisons between sky brightness NPS CCD observations and atlas predictions. (Left) Plots comparing CCD observations to the predictions of the atlas (upper graph, aerosol clarity K = 1; lower graph, K = 0.5). (Right) Fit residuals (observed minus predicted values) for the SQM-based calibration versus CCD NPS observations (upper histogram, K = 1; lower histogram, K = 0.5).
Tables
- 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 brightness Artificial brightness (μcd/m2) Approximate total brightness (mcd/m2) Color <0.01 <1.74 <0.176 Black 0.01–0.02 1.74–3.48 0.176–0.177 Dark gray 0.02–0.04 3.48–6.96 0.177–0.181 Gray 0.04–0.08 6.96–13.9 0.181–0.188 Dark blue 0.08–0.16 13.9–27.8 0.188–0.202 Blue 0.16–0.32 27.8–55.7 0.202–0.230 Light blue 0.32–0.64 55.7–111 0.230–0.285 Dark green 0.64–1.28 111–223 0.285–0.397 Green 1.28–2.56 223–445 0.397–0.619 Yellow 2.56–5.12 445–890 0.619–1.065 Orange 5.12–10.2 890–1780 1.07–1.96 Red 10.2–20.5 1780–3560 1.96–3.74 Magenta 20.5–41 3560–7130 3.74–7.30 Pink >41 >7130 >7.30 White - Table 2 Percentages of population and area under the specified artificial sky brightness (μcd/m2).
Country Brightness (μcd/m2) ≤1.7 >1.7 >14 >87 >688 >3000 ≤1.7 >1.7 >14 >87 >688 >3000 Population (%) Area (%) Afghanistan 39.1 60.9 37.2 26.5 11.6 0.0 79.4 20.6 4.0 0.8 0.0 0.0 Albania 0.0 100.0 98.5 75.6 37.1 10.3 0.0 100.0 87.5 23.8 1.7 0.0 Algeria 0.3 99.7 98.5 91.9 52.1 19.2 66.4 33.6 19.3 8.7 1.1 0.2 American Samoa* 0.0 100.0 100.0 99.7 0.0 0.0 0.0 100.0 100.0 97.0 0.0 0.0 Andorra 0.0 100.0 100.0 100.0 43.6 0.0 0.0 100.0 100.0 98.1 1.5 0.0 Angola 55.2 44.8 33.2 27.5 15.2 7.0 88.5 11.5 2.9 0.8 0.2 0.0 Anguilla* 0.0 100.0 100.0 99.3 0.0 0.0 0.0 100.0 100.0 95.5 0.0 0.0 Antigua and Barbuda 0.0 100.0 100.0 100.0 58.1 0.0 0.0 100.0 100.0 98.7 13.7 0.0 Argentina 1.4 98.6 94.3 87.3 75.8 57.7 38.4 61.6 26.0 6.1 0.9 0.2 Armenia 0.0 100.0 86.3 57.9 31.3 0.0 0.0 100.0 35.1 6.2 0.3 0.0 Aruba* 0.0 100.0 100.0 100.0 68.3 0.0 0.0 100.0 100.0 100.0 23.9 0.0 Australia 2.0 98.0 94.7 88.0 66.7 13.1 88.1 11.9 3.4 0.9 0.2 0.0 Austria 0.0 100.0 99.9 88.7 35.7 10.3 0.0 100.0 97.8 40.0 1.8 0.1 Azerbaijan 0.0 100.0 95.2 71.2 34.6 15.3 18.6 81.4 51.1 13.0 1.3 0.1 Bangladesh 1.1 98.9 79.2 32.2 10.4 0.0 5.3 94.7 60.7 11.5 0.6 0.0 Barbados 0.0 100.0 100.0 100.0 6.0 0.0 0.0 100.0 100.0 99.7 1.4 0.0 Belarus 0.0 100.0 92.7 74.9 48.5 12.0 0.0 100.0 63.2 10.3 0.9 0.1 Belgium 0.0 100.0 100.0 100.0 86.8 22.2 0.0 100.0 100.0 100.0 51.1 2.6 Belize 5.6 94.4 77.8 55.9 4.2 0.0 33.2 66.8 19.7 3.0 0.0 0.0 Benin 34.4 65.6 44.1 27.8 6.6 0.0 84.5 15.5 3.8 1.0 0.0 0.0 Bhutan 12.3 87.7 51.0 20.7 0.0 0.0 43.6 56.4 8.6 0.4 0.0 0.0 Bolivia 13.0 87.0 72.5 63.4 48.9 12.0 77.2 22.8 5.5 1.2 0.1 0.0 Bosnia and Herzegovina 0.0 100.0 98.9 79.0 26.2 0.0 0.0 100.0 88.7 26.0 0.7 0.0 Botswana 22.7 77.3 59.3 43.0 11.5 0.0 89.6 10.4 2.2 0.4 0.0 0.0 Brazil 1.2 98.8 94.7 86.7 62.5 32.3 52.6 47.4 21.6 5.7 0.7 0.1 British Virgin Islands* 0.0 100.0 100.0 100.0 0.0 0.0 0.0 100.0 100.0 100.0 0.0 0.0 Brunei 0.0 100.0 99.9 98.8 91.3 44.9 0.0 100.0 76.4 44.8 12.5 1.6 Bulgaria 0.0 100.0 99.2 77.3 37.0 4.9 0.0 100.0 94.6 19.5 0.9 0.0 Burkina Faso 59.2 40.8 23.4 16.9 10.9 0.0 84.5 15.5 2.7 0.5 0.1 0.0 Burundi 69.5 30.5 9.3 5.2 0.0 0.0 82.8 17.2 1.9 0.3 0.0 0.0 Cambodia 30.0 70.0 30.9 17.2 9.8 0.0 72.4 27.6 4.4 0.8 0.1 0.0 Cameroon 44.6 55.4 42.1 29.3 19.9 0.0 88.0 12.0 3.0 0.5 0.1 0.0 Canada 0.2 99.8 98.9 94.6 76.2 48.3 80.8 19.2 9.0 2.7 0.3 0.1 Cape Verde 1.4 98.6 80.8 42.7 30.2 0.0 24.6 75.4 25.9 4.0 0.5 0.0 Cayman Islands* 0.0 100.0 100.0 99.9 67.6 0.0 0.0 100.0 100.0 96.9 14.0 0.0 Central African Republic 78.2 21.8 19.9 17.1 0.0 0.0 99.7 0.3 0.1 0.0 0.0 0.0 Chad 78.7 21.3 14.0 9.5 7.5 0.0 98.2 1.8 0.5 0.1 0.0 0.0 Chile 0.8 99.2 94.5 87.5 74.4 39.7 51.4 48.6 18.4 5.1 0.7 0.1 China 0.9 99.1 88.9 64.6 32.5 11.9 44.8 55.2 30.0 10.8 1.6 0.2 Christmas Island* 0.0 100.0 99.9 74.3 0.0 0.0 0.0 100.0 49.1 6.9 0.0 0.0 Cocos Islands* 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 Colombia 3.0 97.0 89.3 75.0 54.6 18.7 55.8 44.2 22.1 5.2 0.5 0.0 Comoros 38.2 61.8 38.2 15.6 0.0 0.0 64.5 35.5 6.2 0.8 0.0 0.0 Congo 26.2 73.8 64.9 57.6 49.0 4.7 87.6 12.4 3.6 1.1 0.2 0.0 Congo, Democratic Republic of the Congo 69.6 30.4 22.2 17.5 11.8 3.3 95.8 4.2 1.0 0.2 0.0 0.0 Cook Islands* 0.0 100.0 85.4 0.0 0.0 0.0 0.0 100.0 34.7 0.0 0.0 0.0 Costa Rica 0.0 100.0 97.3 81.8 52.9 2.4 0.4 99.6 70.4 18.3 1.6 0.0 Cote d’Ivoire 17.8 82.2 54.2 33.6 19.6 3.5 50.4 49.6 11.1 1.5 0.2 0.0 Croatia 0.0 100.0 100.0 95.2 50.5 21.2 0.0 100.0 98.9 62.2 4.0 0.4 Cuba 0.6 99.4 90.0 66.2 39.5 1.9 6.7 93.3 52.3 10.9 0.9 0.0 Cyprus 0.0 100.0 99.9 98.1 71.4 10.5 0.0 100.0 99.1 72.2 8.4 0.2 Czech Republic 0.0 100.0 100.0 97.5 42.8 7.3 0.0 100.0 100.0 82.3 3.6 0.2 Denmark 0.0 100.0 99.9 89.3 38.5 7.3 0.0 100.0 99.2 47.9 2.9 0.1 Djibouti 48.9 51.1 39.7 0.8 0.0 0.0 82.3 17.7 2.8 0.1 0.0 0.0 Dominica 0.0 100.0 94.5 43.7 0.0 0.0 0.0 100.0 44.4 5.7 0.0 0.0 Dominican Republic 0.0 100.0 98.1 82.3 57.6 22.6 0.2 99.8 79.8 23.0 2.8 0.3 Ecuador 0.4 99.6 95.3 78.3 50.0 17.7 17.2 82.8 53.4 14.9 1.7 0.2 Egypt 0.0 100.0 99.9 99.8 97.5 37.1 52.4 47.6 26.5 12.6 4.9 0.5 El Salvador 0.0 100.0 94.9 67.3 24.2 0.0 0.0 100.0 80.2 18.7 1.1 0.0 Equatorial Guinea 17.2 82.8 54.2 39.1 20.0 0.0 20.4 79.6 22.3 3.6 0.3 0.0 Eritrea 65.1 34.9 21.9 13.3 0.0 0.0 95.5 4.5 0.7 0.1 0.0 0.0 Estonia 0.2 99.8 97.4 83.9 60.5 31.8 2.7 97.3 75.1 19.7 2.3 0.3 Ethiopia 73.9 26.1 11.3 6.1 1.5 0.0 93.4 6.6 1.2 0.2 0.0 0.0 Falkland Islands* 17.6 82.4 80.2 67.8 0.0 0.0 88.7 11.3 1.8 0.2 0.0 0.0 Faroe Islands* 0.0 100.0 96.5 74.5 12.6 0.0 0.1 99.9 84.3 21.5 0.3 0.0 Fiji 27.4 72.6 49.1 29.9 0.0 0.0 67.7 32.3 7.5 1.3 0.0 0.0 Finland 0.0 100.0 99.7 95.7 68.0 33.7 2.8 97.2 73.9 27.6 2.9 0.4 France 0.0 100.0 100.0 94.3 58.9 26.6 0.0 100.0 100.0 64.5 6.7 0.7 French Guiana* 7.8 92.2 88.4 77.9 36.7 0.0 88.3 11.7 2.9 0.7 0.1 0.0 French Polynesia* 0.0 100.0 98.7 80.8 4.9 0.0 0.0 100.0 59.6 10.9 0.2 0.0 Gabon 22.0 78.0 69.4 56.9 38.7 0.2 77.5 22.5 7.9 2.0 0.3 0.0 Gaza Strip* 0.0 100.0 100.0 100.0 95.1 0.0 0.0 100.0 100.0 100.0 68.1 0.0 Georgia 0.0 100.0 92.2 63.6 36.7 4.5 0.0 100.0 49.8 10.8 0.8 0.0 Germany 0.0 100.0 100.0 96.0 41.6 2.7 0.0 100.0 100.0 74.2 4.8 0.1 Ghana 15.5 84.5 60.6 37.1 21.4 0.4 51.5 48.5 16.3 3.4 0.5 0.0 Gibraltar* 0.0 100.0 100.0 100.0 100.0 41.9 0.0 100.0 100.0 100.0 100.0 28.6 Greece 0.0 100.0 99.8 93.2 66.0 41.9 0.0 100.0 96.3 40.1 3.0 0.5 Greenland* 13.3 86.7 86.6 78.1 3.9 0.0 99.9 0.1 0.0 0.0 0.0 0.0 Grenada 0.0 100.0 100.0 76.3 0.0 0.0 0.0 100.0 100.0 39.8 0.0 0.0 Guadeloupe* 0.0 100.0 100.0 99.7 60.2 1.7 0.0 100.0 100.0 87.5 11.3 0.1 Guam* 0.0 100.0 100.0 100.0 82.9 0.0 0.0 100.0 100.0 95.8 27.4 0.0 Guatemala 2.2 97.8 84.8 46.3 20.2 0.5 25.4 74.6 38.9 7.2 0.6 0.0 Guernsey* 0.0 100.0 100.0 91.1 0.0 0.0 0.0 100.0 100.0 68.7 0.0 0.0 Guinea 75.8 24.2 15.3 9.6 0.0 0.0 95.1 4.9 0.8 0.2 0.0 0.0 Guinea-Bissau 68.7 31.3 28.5 23.3 0.0 0.0 97.5 2.5 0.6 0.1 0.0 0.0 Guyana 26.3 73.7 55.5 43.5 5.8 0.0 94.3 5.7 1.2 0.2 0.0 0.0 Haiti 28.1 71.9 41.1 30.7 19.2 0.0 43.5 56.5 12.6 2.5 0.3 0.0 Honduras 2.1 97.9 78.5 51.2 33.2 2.2 28.9 71.1 34.2 6.0 0.5 0.0 Hungary 0.0 100.0 100.0 86.0 38.5 9.8 0.0 100.0 100.0 41.1 2.1 0.2 Iceland 0.7 99.3 95.0 91.6 73.8 38.7 36.0 64.0 24.4 7.6 0.6 0.1 India 0.2 99.8 93.9 58.5 19.5 5.9 6.8 93.2 72.5 24.7 1.5 0.1 Indonesia 7.0 93.0 83.2 64.5 24.8 6.3 60.9 39.1 17.7 6.4 0.6 0.1 Iran 0.2 99.8 97.9 88.5 64.0 17.1 17.0 83.0 55.5 18.1 2.6 0.3 Iraq 0.1 99.9 99.1 95.6 76.2 49.4 28.7 71.3 53.7 33.2 9.0 2.5 Ireland 0.0 100.0 99.6 83.9 45.2 18.5 0.0 100.0 94.6 39.4 2.0 0.3 Isle of Man* 0.0 100.0 99.8 77.4 42.7 0.0 0.0 100.0 97.8 31.5 2.8 0.0 Israel 0.0 100.0 100.0 99.9 97.6 61.0 0.0 100.0 98.2 76.3 41.9 8.1 Italy 0.0 100.0 100.0 99.6 76.9 26.7 0.0 100.0 100.0 90.3 19.7 1.3 Jamaica 0.0 100.0 100.0 86.0 47.2 4.1 0.0 100.0 100.0 41.7 2.9 0.1 Japan 0.0 100.0 99.9 96.7 70.4 29.9 0.1 99.9 91.1 39.2 7.1 1.0 Jersey* 0.0 100.0 100.0 98.9 35.8 0.0 0.0 100.0 100.0 91.5 6.5 0.0 Jordan 0.1 99.9 99.7 98.8 80.5 24.7 13.6 86.4 52.0 22.2 4.2 0.2 Kazakhstan 7.7 92.3 80.5 66.0 45.0 12.3 60.9 39.1 11.3 2.9 0.5 0.1 Kenya 34.9 65.1 31.6 18.3 9.1 0.0 85.2 14.8 3.3 0.7 0.1 0.0 Kuwait 0.0 100.0 100.0 100.0 100.0 98.1 0.0 100.0 100.0 92.0 50.9 11.5 Kyrgyzstan 1.8 98.2 88.8 60.5 18.6 0.0 35.9 64.1 19.3 3.6 0.1 0.0 Laos 41.0 59.0 35.7 20.1 8.3 0.0 73.7 26.3 5.0 1.0 0.1 0.0 Latvia 0.0 100.0 89.2 71.9 46.8 21.2 0.0 100.0 48.3 9.2 1.0 0.1 Lebanon 0.0 100.0 100.0 99.6 63.0 28.4 0.0 100.0 100.0 88.5 18.3 1.7 Lesotho 18.1 81.9 45.9 21.8 0.0 0.0 45.2 54.8 9.2 1.0 0.0 0.0 Liberia 73.6 26.4 15.7 9.2 0.0 0.0 95.1 4.9 0.9 0.1 0.0 0.0 Libya 0.9 99.1 98.7 97.3 84.7 52.7 71.1 28.9 12.4 4.1 0.7 0.1 Liechtenstein 0.0 100.0 100.0 100.0 0.0 0.0 0.0 100.0 100.0 93.7 0.0 0.0 Lithuania 0.0 100.0 93.0 66.7 41.9 7.8 0.0 100.0 72.0 11.7 1.0 0.0 Luxembourg 0.0 100.0 100.0 100.0 60.1 6.9 0.0 100.0 100.0 100.0 18.9 0.2 Macedonia 0.0 100.0 100.0 84.2 42.4 10.8 0.0 100.0 100.0 23.4 1.4 0.1 Madagascar 76.7 23.3 15.3 9.6 0.0 0.0 97.4 2.6 0.5 0.1 0.0 0.0 Malawi 29.7 70.3 27.9 13.4 0.7 0.0 62.3 37.7 6.5 1.1 0.0 0.0 Malaysia 1.7 98.3 94.2 88.9 67.9 34.6 32.3 67.7 40.7 19.8 3.7 0.6 Mali 64.6 35.4 27.9 24.1 12.6 0.0 97.0 3.0 0.6 0.1 0.0 0.0 Malta 0.0 100.0 100.0 100.0 99.8 41.5 0.0 100.0 100.0 100.0 88.5 16.7 Martinique* 0.0 100.0 100.0 100.0 65.5 7.2 0.0 100.0 100.0 98.8 25.2 0.3 Mauritania 61.1 38.9 32.7 28.2 21.4 0.0 98.6 1.4 0.3 0.1 0.0 0.0 Mauritius 0.0 100.0 100.0 95.1 29.9 0.0 0.0 100.0 100.0 70.9 4.3 0.0 Mayotte* 0.0 100.0 100.0 69.5 0.0 0.0 0.0 100.0 100.0 37.6 0.0 0.0 Mexico 0.5 99.5 95.8 83.3 58.3 22.8 20.8 79.2 37.9 11.6 1.7 0.2 Midway Islands* 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 Moldova 0.0 100.0 89.9 43.8 18.6 0.0 0.0 100.0 68.7 8.2 0.5 0.0 Mongolia 31.4 68.6 63.2 51.6 36.7 0.0 95.6 4.4 0.8 0.1 0.0 0.0 Montenegro 0.0 100.0 97.2 80.6 44.7 11.7 0.0 100.0 81.0 24.9 1.5 0.1 Montserrat* 0.0 100.0 97.8 0.0 0.0 0.0 0.0 100.0 17.9 0.0 0.0 0.0 Morocco 0.9 99.1 91.0 67.5 49.3 29.3 26.6 73.4 39.8 11.3 1.4 0.2 Mozambique 55.8 44.2 28.3 20.3 11.9 2.9 87.2 12.8 2.9 0.6 0.1 0.0 Myanmar 26.2 73.8 39.9 21.5 9.5 0.6 70.3 29.7 5.6 1.0 0.1 0.0 Namibia 31.3 68.7 50.1 37.1 17.4 0.0 92.3 7.7 1.5 0.2 0.0 0.0 Nauru 0.0 100.0 100.0 100.0 0.0 0.0 0.0 100.0 100.0 100.0 0.0 0.0 Nepal 21.9 78.1 45.7 18.1 0.0 0.0 60.5 39.5 10.2 1.2 0.0 0.0 Netherlands 0.0 100.0 100.0 100.0 81.2 26.2 0.0 100.0 100.0 99.4 42.5 7.2 Netherlands Antilles* 0.0 100.0 100.0 99.2 93.5 0.7 0.0 100.0 100.0 79.6 30.0 1.7 New Caledonia* 7.6 92.4 79.2 67.2 48.4 0.0 38.9 61.1 16.3 3.9 0.6 0.0 New Zealand 2.8 97.2 91.4 83.4 56.4 4.8 53.1 46.9 15.1 3.5 0.5 0.0 Nicaragua 16.9 83.1 65.5 50.7 24.3 0.0 64.7 35.3 11.8 2.5 0.2 0.0 Niger 73.2 26.8 18.7 14.6 6.5 0.0 97.3 2.7 0.6 0.1 0.0 0.0 Nigeria 25.4 74.6 52.6 35.6 13.8 0.5 59.7 40.3 15.8 7.0 1.4 0.2 Niue* 97.3 2.7 0.0 0.0 0.0 0.0 99.5 0.5 0.0 0.0 0.0 0.0 Norfolk Island* 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 North Korea 27.3 72.7 42.4 15.4 1.1 0.0 61.9 38.1 10.0 1.8 0.0 0.0 Northern Mariana Islands* 0.0 100.0 100.0 100.0 0.0 0.0 0.0 100.0 100.0 100.0 0.0 0.0 Norway 0.0 100.0 99.7 95.5 69.1 28.7 1.4 98.6 66.1 22.1 1.8 0.2 Oman 0.1 99.9 98.9 96.1 80.5 34.1 15.1 84.9 54.3 23.2 3.2 0.5 Pakistan 3.4 96.6 89.8 58.6 19.7 6.6 45.9 54.1 32.2 9.4 0.5 0.1 Panama 6.3 93.7 86.0 73.0 54.1 17.2 42.5 57.5 27.0 7.4 1.2 0.1 Papua New Guinea 68.3 31.7 18.8 10.9 5.3 0.1 89.4 10.6 2.5 0.6 0.1 0.0 Paraguay 1.6 98.4 86.4 70.9 55.0 34.7 57.2 42.8 18.2 3.9 0.6 0.1 Peru 8.7 91.3 73.2 63.4 48.3 16.4 62.4 37.6 8.7 1.7 0.2 0.0 Philippines 8.7 91.3 67.2 47.6 26.5 7.2 35.6 64.4 20.9 6.1 0.7 0.1 Poland 0.0 100.0 100.0 93.9 50.1 13.9 0.0 100.0 99.7 67.5 4.5 0.3 Portugal 0.0 100.0 100.0 98.3 76.7 35.4 0.0 100.0 100.0 71.2 12.8 1.3 Puerto Rico* 0.0 100.0 100.0 100.0 71.0 25.5 0.0 100.0 100.0 99.9 28.6 3.4 Qatar 0.0 100.0 100.0 100.0 99.8 96.7 0.0 100.0 100.0 97.0 54.6 16.3 Reunion* 0.0 100.0 100.0 95.2 43.8 0.0 0.0 100.0 99.7 51.0 3.7 0.0 Romania 0.0 100.0 99.3 65.7 32.3 10.5 0.0 100.0 92.5 24.3 1.3 0.1 Russia 1.7 98.3 92.7 80.9 61.8 32.0 66.5 33.5 16.0 4.9 0.6 0.1 Rwanda 9.9 90.1 28.0 10.2 0.5 0.0 25.0 75.0 13.4 1.9 0.0 0.0 Samoa 31.7 68.3 62.1 35.6 0.0 0.0 79.6 20.4 4.3 0.8 0.0 0.0 San Marino 0.0 100.0 100.0 100.0 100.0 0.0 0.0 100.0 100.0 100.0 100.0 0.0 Sao Tome and Principe 5.6 94.4 80.5 41.0 0.0 0.0 25.5 74.5 26.1 5.2 0.0 0.0 Saudi Arabia 0.0 100.0 99.8 99.1 95.9 83.0 28.3 71.7 43.0 17.3 3.3 0.6 Senegal 33.5 66.5 45.5 34.0 15.5 0.0 81.9 18.1 4.3 0.9 0.1 0.0 Serbia 0.0 100.0 100.0 92.4 39.4 13.6 0.0 100.0 100.0 57.9 3.1 0.2 Seychelles 0.0 100.0 100.0 76.5 4.6 0.0 0.0 100.0 99.6 55.6 0.4 0.0 Sierra Leone 72.5 27.5 19.3 10.1 0.0 0.0 91.1 8.9 1.3 0.1 0.0 0.0 Singapore 0.0 100.0 100.0 100.0 100.0 100.0 0.0 100.0 100.0 100.0 100.0 100.0 Slovakia 0.0 100.0 99.8 82.3 23.8 4.8 0.0 100.0 98.6 46.8 1.8 0.2 Slovenia 0.0 100.0 100.0 95.9 27.0 0.4 0.0 100.0 100.0 68.4 1.9 0.0 Solomon Islands 61.6 38.4 33.7 30.6 0.0 0.0 94.3 5.7 1.2 0.2 0.0 0.0 Somalia 74.4 25.6 21.7 13.3 0.0 0.0 98.8 1.2 0.2 0.0 0.0 0.0 South Africa 2.2 97.8 83.7 66.8 46.1 10.9 37.7 62.3 27.4 7.5 1.1 0.1 South Korea 0.0 100.0 100.0 99.8 91.0 66.4 0.0 100.0 100.0 89.4 19.1 3.5 Spain 0.0 100.0 100.0 96.1 75.2 41.5 0.0 100.0 98.6 46.5 6.7 0.9 Sri Lanka 0.7 99.3 76.4 29.8 2.5 0.0 11.4 88.6 33.9 5.4 0.2 0.0 St. Helena* 16.1 83.9 0.0 0.0 0.0 0.0 51.4 48.6 0.9 0.0 0.0 0.0 St. Kitts and Nevis 0.0 100.0 100.0 99.5 59.7 0.0 0.0 100.0 100.0 56.9 5.0 0.0 St. Lucia 0.0 100.0 100.0 96.7 44.2 0.0 0.0 100.0 100.0 63.1 1.8 0.0 St. Pierre and Miquelon* 3.7 96.3 48.1 48.1 0.0 0.0 26.2 73.8 4.3 0.4 0.0 0.0 Sudan 59.3 40.7 29.6 22.5 11.6 1.9 93.9 6.1 1.6 0.4 0.1 0.0 Suriname 10.8 89.2 85.4 77.6 51.5 7.1 87.0 13.0 3.7 1.1 0.1 0.0 Swaziland 0.0 100.0 76.3 33.0 9.8 0.0 0.0 100.0 64.5 8.3 0.3 0.0 Sweden 0.0 100.0 99.9 96.7 62.0 25.7 5.6 94.4 60.3 21.4 1.6 0.2 Switzerland 0.0 100.0 100.0 96.9 34.0 0.0 0.0 100.0 100.0 57.9 2.6 0.0 Syria 0.4 99.6 91.2 68.5 21.5 1.3 23.3 76.7 38.2 12.4 0.4 0.0 Tajikistan 3.8 96.2 87.8 55.9 14.1 0.0 57.5 42.5 19.4 3.1 0.1 0.0 Tanzania 62.7 37.3 23.0 15.4 8.8 0.0 92.5 7.5 1.3 0.2 0.0 0.0 Thailand 0.2 99.8 92.5 61.5 32.3 16.3 4.4 95.6 64.2 18.0 2.4 0.3 The Gambia 36.1 63.9 52.8 43.6 0.0 0.0 77.2 22.8 6.7 2.6 0.0 0.0 Timor-Leste 30.7 69.3 30.8 15.2 4.4 0.0 57.3 42.7 6.7 1.0 0.1 0.0 Togo 35.8 64.2 48.0 30.8 22.7 0.0 76.7 23.3 6.2 1.4 0.3 0.0 Tokelau* 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 Tonga 0.0 100.0 98.4 66.5 0.0 0.0 0.0 100.0 79.9 13.0 0.0 0.0 Trinidad and Tobago 0.0 100.0 100.0 100.0 94.3 50.2 0.0 100.0 100.0 96.6 43.5 5.2 Tunisia 0.0 100.0 99.4 80.4 48.5 16.5 9.8 90.2 61.6 17.2 1.8 0.2 Turkey 0.0 100.0 97.8 77.7 49.9 24.3 0.0 100.0 87.4 25.7 2.2 0.3 Turkmenistan 1.3 98.7 95.9 87.5 47.3 19.5 46.0 54.0 25.0 8.5 1.3 0.2 Uganda 60.6 39.4 17.7 9.8 4.1 0.0 83.3 16.7 3.2 0.7 0.0 0.0 Ukraine 0.1 99.9 91.3 65.0 29.9 2.9 0.4 99.6 62.8 11.1 0.9 0.1 United Arab Emirates 0.0 100.0 100.0 100.0 99.3 92.7 0.0 100.0 92.3 60.9 23.4 5.7 United Kingdom 0.0 100.0 99.9 98.2 77.0 26.0 3.6 96.4 86.4 60.8 13.5 1.4 United States 0.0 100.0 99.7 97.2 77.6 36.9 30.4 69.6 46.9 23.2 3.6 0.6 Uruguay 1.3 98.7 94.6 89.1 75.3 34.8 19.8 80.2 27.9 6.7 0.9 0.1 Uzbekistan 0.9 99.1 96.5 81.0 19.7 2.7 56.0 44.0 25.9 10.7 0.6 0.1 Vanuatu 41.1 58.9 40.3 14.0 0.0 0.0 69.0 31.0 11.5 7.9 1.4 0.2 Venezuela 1.2 98.8 96.7 91.2 73.0 33.7 52.5 47.5 30.7 14.0 3.3 0.8 Vietnam 3.2 96.8 85.6 60.6 25.2 8.2 21.3 78.7 42.5 17.5 3.0 0.7 Virgin Islands* 0.0 100.0 100.0 99.9 75.9 0.0 0.0 100.0 100.0 99.1 37.2 0.0 Wallis and Futuna* 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 West Bank* 0.0 100.0 100.0 100.0 94.6 42.4 0.0 100.0 100.0 100.0 61.1 4.1 Western Sahara* 4.1 95.9 95.6 95.5 90.6 5.9 93.7 6.3 1.5 0.4 0.1 0.0 Yemen 2.7 97.3 52.5 27.9 14.4 1.4 45.5 54.5 18.9 4.9 0.5 0.1 Zambia 43.8 56.2 42.2 35.1 16.1 0.0 85.9 14.1 3.7 0.8 0.1 0.0 Zimbabwe 45.6 54.4 37.5 28.4 2.5 0.0 77.2 22.8 4.3 0.7 0.0 0.0 European Union 0.0 100.0 99.8 94.0 59.5 20.5 1.3 98.7 88.4 48.7 6.0 0.6 World 8.0 92.0 83.2 63.7 35.9 13.9 60.3 39.7 22.5 8.6 1.2 2 *Nonindependent territories.
- Table 3 Performance of atlas predictions for different data sets.
Negative values indicate that the observed skies were brighter than predicted. The top entries are used to calibrate the atlas. The final three entries are independent data sets used for verification. PS, professional scientist; CS, citizen scientist.
Provider Location Mode Mean σ Scientist All data Worldwide Both 0.008 0.17 Mixed Various Catalonia, Spain Car 0.03 0.14 PS Universidad Complutense de Madrid Madrid, Spain Car −0.04 0.17 PS Kyba/Sanchez Berlin, Germany Car 0.12 0.11 PS Globe at Night Worldwide Hand −0.21 0.34 CS Haenel/Frank Europe and North America Hand 0.05 0.17 PS Unihedron Worldwide Hand −0.01 0.24 CS Loss of the Night app Worldwide Hand −0.02 0.29 CS Espey/Owens Ireland Hand −0.08 0.14 Mixed Royal Astronomical Society of Canada Canada Hand −0.01 0.28 CS Giubbilini Italy Hand 0.03 0.09 PS International Dark Sky Places Wales Hand 0.01 0.27 CS U.S. National Park Service United States CCD 0.11 0.13 PS Falchi Italy CCD −0.04 0.19 PS SQM stations Worldwide Permanent stations −0.06 0.46 Mixed
