Cloud monitoring system at Telescope Array site by Visible Fisheye CCD

Abstract

The Telescope Array (TA) is an international experiment studying ultra-high energy cosmic rays. TA uses the fluorescence detection technique to observe cosmic rays. In order to estimate the energy of cosmic rays with a fluorescence detector (FD), it is necessary to measure the condition of the observation area. Clouds affect the accuracy of the energy estimation. It is necessary to measure the existence of clouds and their direction in the Field Of View (FOV) of the FD. We developed a cloud monitoring system to measure the night sky weather using a CCD camera. In this report, we present our progress on our CCD cloud monitoring system.