Night sky
The night sky is usually a special term used to describe the sky seen at night. This term is often associated with astronomical objects, such as stars, the moon and planets, which can be seen in the sunny sky in the sky after the day together. The night sky and its research, from ancient times to the present are part of history and culture. In the past, for example, farmers to the night sky state when the calendar, to determine the time of plant cultivation. Many cultures also link the constellations and bright stars in the sky with gods, myths and legends. The development of astrology in ancient times is believed to be based on the influence of astronomical objects on earth and the messages conveyed. The scientific research and observation of the night sky and celestial bodies, but also make astronomy a science. The visibility of celestial bodies in the night sky is affected by light pollution. In history, the moon in the night sky will increase the lighting of the environment and hinder astronomical observations. However, with the increase in artificial light caused by light pollution, has made the problem of observation of the sky increasingly serious. Special color filters and improvements to luminaires help to alleviate this problem, but whether for professional or amateur optical astronomers, the best place to observe or stay away from the city area. ...