Clouds have important effects on astronomical observations.Cloud cover is an important indicator of the quality of an astronomical site.The infrared cloud imager which locates in Yaoan astronomical station,is used for the real-time acquisition of all-sky infrared cloud image with high spatial resolution.Combining the actual observations of space debris,according to astronomical nights strictly,we make statistics and analysis of cloud cover at night accumulated in one year (from 2015-08-01 to 2016-07-31).Annual average cloud cover at night at Yaoan astronomical station is 4.42 ten percent,and there are 236 available astronomy nights,including 98 photometric nights,44 half-photometric nights,and 94 spectroscopic nights.The cloud cover has obvious characteristics of two seasons:the rainy season with a significant increase in cloud cover is from May to October,and the observation conditions are worst in July;The dry season is from November to April with low cloud cover,there are more than 23 available astronomy nights monthly,the most numerous photometric nights are in January,and the most available astronomy nights are in March.Combined with the threat level of cloud for astronomical observation,we make statistics of the total time of different cloud covers and the monthly distribution of cloud covers,to assess the meteorological conditions of the station,and to provide a reference for reasonable arrangements of the astronomical observations.%云对天文观测具有重要影响,云量是衡量天文台址质量的重要指标.位于姚安天文观测站的红外云量仪,用于获取实时的全天高空间分辨率云图.结合空间碎片的实际观测,严格按照天文夜对累积1 yr (2015-08-01-2016-07-31)的夜间云量数据进行统计和分析.姚安站的年平均夜间云量为4.42成,年天文可用夜为236个,其中测光夜98个,半测光夜44个,光谱夜94个.云量具有明显的两季特征:5月至10月间为雨季,云量显著增多,其中7月份观测条件最差;11月至次年4月为旱季,云量较少,每月的天文可用夜均在23个以上,其中1月份的测光夜最多,3月份的天文可用夜最多.结合云层对天文观测的威胁程度,统计不同云量的总时间和每月的云量分布情况,评估观测站的气象条件,为合理安排观测计划提供参考.
展开▼
