Simultaneous observation of time variable TeV gamma-ray objects in optical wavelength and monitoring of night sky

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Gamma-ray emission from Active Galactic Nuclei is highly variable in time and the reported time scale of its variation is as short as 15 minutes. Simultaneous observation at other wavelength should be done at the same longitude as gamma-ray observation.Is this research we set a small optical telescope next to the KANGAROO gamma-ray telescope in Woomera, South Australia to study short time variability simultaneously. Also we aim to monitor night sky condition around the gamma-ray objects for quality check of gamma-ray observation by atmospheric Cherenkov method.This year we operated the optical telescope system in Kashiwa campus, Chiba, as a test and shipped it to Woomera for test observation. We developed a full automated observation system using Linux operating system so that we can utilize network. It controls the telescope mount and obtains data from the cooled CCD camera. At Kashiwa we succeeded in observing an AGN, Mrk421. At Woomera, we had to setup the telescope axis every night since the automated telescope shelter was not in time which required long time each night. However, we could measure stars at various zenith angles and with Johnson UBVRI filters. Comparing data with the model calculation of atmosphere, we could know the properties of atmosphere in Woomera, which is an important information when we estimate gamma-ray energy from observed number of photons in Cherenkov observation.