condition mean min max 4 h after light 6.59104 5.96645 7.21563 8 h after light 8.905575 8.62996 9.18119 12 h after light 8.947235 7.77957 10.1149 4 h after dark 10.7573 10.624 10.8906 8 h after dark 10.45115 10.1267 10.7756 12 h after dark 12.92485 12.8378 13.0119