The old professor says that light pollution is the bane of astronomers and other sky watchers. It began as soon as they began to be bothered by human produced light....be it candles, oil lamps, or whatever. Early sky watchers moved away from such concentrations of light. Even astronomers such as Tycho Brahe moved to a remote island to escape the smoke and light pollution of the oil lamps of Renaissance cities. The big problems began with electric lights and the movement of cities to the vicinities of astronomic observatories. I guess some tried to do something about it around the beginning of the 20th century. Today, the mercury vapor lights and sodium vapor lights are the real culprits. Few good places are left for the perfect darkness desired by astronomers.
when the first light bulb was lit its just too much light to see the stars and what not, so ..when the light become too much for astronomers to see, thats when it began i dont think there is an exact date.
It started when electric lights became commonplace. It is the general brightening of the whole sky caused by to many bright outdoor lights. Mount Wilson Observatory is too close to Los Angeles to be a major observatory today because the sky is now so bright. But when it was built back in the early 1900s it was plenty dark and it was the top observatory in the world.
