Astronomers at the Shanghai Observatory are facing a serious problem. Urban growth in nearby Shanghai has been contributing to light pollution for a long time, but is now reaching an unacceptable level. This light pollution dilemma has made the observatory's 1.56 meter telescope nearly unusable. Light pollution is more than a mere inconvenience, however. The high levels of artificial light has caused the observatory to refrain from participating in world-class research projects.
The above image shows a world map of light pollution levels. According to a 1985 recommendation by the International Astronomical Union (IAU), world-class observatories need dark skies, where the artificial light level is less than 10%. Light pollution levels at Shanghai's Sheshan observatory have been measured to be as high as 591%. As one could imagine, this would seriously hamper observations of dim and distant objects.
So now, Shanghai's astronomers must face a difficult move. The observatory, if it is to be of any use, must be relocated to a much darker site. One dark-sky site being considered is Tianhuangping, Anji City. Tianhuangping is situated at an altitude of 1,000 meters, where observing conditions should be greatly improved. Zhejiang authorities have also agreed to enact light pollution protection legislation for the area.
Light pollution is a problem that nearly all astronomers, both amateur and professional, must contend with. Some areas have it worse than others, while some are barely affected. It would be nice to see companies and institutions begin controlling light scatter, but chances are slim. So if your neighbor is an amateur astronomer, be nice and leave the lights off for them...
Clear (and dark) skies!