Light pollution? Well, it might be a another silly jargon created by many astronomers; but, if you ponder alot about it, light pollution can be a serious problems. Truly, light pollution is a regard to light in an excessive way, but deep beneath, this kind of pollutant contain serious threat to environment, health, and further on social issue, etc. Ugh.
Okay, disregard all the complexity, let us go easy talk in astronomy only. For astronomy, light pollution is excessive light, light which created by man, byproduct of human activities. So excessive the light, when flooding the night sky, can reduce the contrast of the sky, making it more difficult to observe dimmer objects. This is the problem for most astronomer-goers, that is, the less the dark sky, the less the fun!
But, it is unrealistic to inhibit this excessiveness, since artificial light is the sign of human activites. So, the realistic choice for most astronomy-goers, find the darker place somewhere far from the city, in a rural countryside, to observe the heaven.
On one occasion, i went to a rural area for site-testing for new observatory. Since the idea is to find the proper site for new observatory, we pick area that should be far from human activities, it should be some miles from nearer town.
So we did, we set up the telescopes, camera, bla bla bla. Do we have a good night sky? Well, cloud and haze are problems, the challenge on sky-gazing. But those are the challenge from nature. What about the challenge from our fellow neighbours? By standard digital-camera, we see that far beyond we see the glaring night due north. Yeah, there is a strong sense of bright light from somewhere in there. But, how strong will that bright light affecting the night sky?
There are numerous indepth methods to measure the brightness and the relation with pollution, but if we can measure in an easy way, why do the harder? Well, since the observation is merely a preliminary, we do the ‘quick-look’ method. That is, by dissecting the light. By dissecting the light, we can have the quantization and see by ourself, do we have a pollutant, or merely another stray-light?
So here we are, after dissecting the light, we see that there is a strong emission of Hg. Hg is for Hydragyrum (meaning: liquide silver) is the chemical name of an element, most known as mercury, mercury is well known as strong signature of Fluorescent Lamp. That is the most common lamp for urban area. After we identified this sign, we can firmly belive to decide, do we have a pollution or not.
Back to my previous statement, light pollution can be a serious problem, since, like any other pollutant, the waste of light is the waste of energy, and the waste of energy, direct or indirect affecting our life. Too complex to discuss the broader aspects of light pollutin, since dispute can be aroused between pros and against between the user of light. But the observation of astronomy can be work as an assessment, and finally verified what have we done with our nature.