Light Pollution Map
Using Google Earth and North American Light Pollution Map overlay

Notes: This map shows a zoomed-in area relative to the previous map. The mountains in the background are the San Bernardino mountains with the highest peaks being Mt. San Antonio (a.k.a., "Mt. Baldy" at about 9,800 feet), Ontario Peak (about 8,700 feet), and Cucamonga Peak (about 8,800 feet). Notice the proximity of the airport. It's this airport and the surrounding industrial warehouses and commercial complexes that create most of the light pollution in the Ontario, Rancho Cucamonga, Chino, Montclair, and other surrounding areas.