Wide field of view cloud monitors used for experiment of ultra high energy cosmic rays

望远镜阵列实验一直在测量超高能量宇宙射线产生的大面积空气阵雨（EASs）发出的空气荧光。由于大气条件影响EAS的测量精度，因此大气监测非常重要。在大气监测方面，研制了配备鱼眼镜头CCD摄像机的云监测仪，安装在荧光探测器的建筑物顶部。在前2年的运行中，达到了99%的利用率。这个比率将在本预算结束后保持不变。我们研究了一种从获得的图片中寻找云的算法。

The Telescope Array experiment has been measuring air fluorescence lights emitted from extensive air showers(EASs) produced by ultra high energy cosmic rays. Since atmospheric condition affects measurement accuracies of EAS, atmospheric monitoring is important. For the atmospheric monitoring, cloud monitors equipped CCD cameras with fisheye-lens were developed, and were installed at the top of buildings of the fluorescence light detector. In the first 2 years operation, availability ratio of 99% was achieved. This ratio will be been keeping beyond the end of this budget. We studied a cloud finding algorithm from obtained pictures.