Observation of the Night Sky Brightness at the Gaomeigu Station

The importance of the night sky brightness is pointed out for the evaluation of the astronomical site. The principle and methods for the determination of the night sky brightness are introduced in this paper. It is shown that the night skey brightness at the Gaomeigu station is 21.49-21.63 mag/◇" inV or 21.80-21.86 mag/◇"in V(λ). The results are also compared with that of some observatories around the world.