关于上海天文台天荒坪江南天池观测站的夜天亮度

NOTE ON THE NIGHT SKY BRIGHTNESS AT THE JIANG-NAN-TIAN-CHI STATION OF SHANGHAI OBSERVATORY

上海天文台在浙江安吉县天荒坪江南天池建立了观测站(地理经度=119°.5978,纬度=30°.4694,高度=958.409m)。为了定量估计该站的夜天亮度,使用安装在25cm口径反射望远镜的CCD照相机,于2008年12月2日的晴夜,做了V波段的测定。该夜的大部分时间里,V波段的大气消光系数约为0.29,天顶附近无星天区的夜天亮度约为20.8/(″)2。但是12月3日晨3h30m以后,天气变得更好,天空透明度增加,夜天亮度降低,在疏散星团M67的外围区域,测得的夜天亮度约为(21.05+1.06*Kv)/(″)2。晴夜的Kv一般在0.15～0.30之间,所以当时的夜天亮度应当≥21.2,在江浙一带,找到夜天亮度这样暗的观测站已经很不错了。

A new station,Jiang-Nan-Tian-Chi station of Shanghai Observatory (λ=119°.5978,φ=30°.4694,height=958.409m),has been established at the Tian Huang Ping of Anji county,Zhejiang province. The night sky brightness at the station was determined on 2008 December 2. The atmospheric extinction coeffficient Kv was equal to 0.29 at that night,and the night sky brightness in V waveband was 20.8/(″)2. The sky brightness was≥21.2 in the morning of 2008 December 3,while the sky transparency became better.