Simultaneous observation of TeV time-variable objects and gamma-ray burst afterglows with an optical telescope

我们在CANGAROO旁边安装了一个小型的自动光学望远镜系统，CANGAROO是一个由四个成像切伦科夫望远镜组成的阵列，用于在南澳大利亚的伍默拉进行高能伽马射线观测，这是日本和澳大利亚机构的合作。该项目的主要目的是监测时变TeV天体，如活动星系核，并在光学波段对伽玛射线爆发余辉进行后续观测。此外，该望远镜还可以通过观测切伦科夫观测视场附近的星光消光来监测大气状况，这在切伦科夫观测中很重要。该系统由一个直径30厘米的施密特-卡塞格伦望远镜（Meade LX200-30）和一个冷却CCD相机（Apogee Ap-7p）组成，由一台基于linux的计算机通过网络控制。它配备了一个带有约翰逊滤光片的自动滤光轮，从而实现了多波长测光。观察小屋有一个自动屋顶，使用可由计算机控制的电机。对于自动操作，它包括各种传感器，如触发屋顶自动关闭的降雨监测器。我们在合作者的帮助下开发了所有这些软件。我们用这个系统成功地拍摄了一些测试图像。这个自动化系统已经在伍默拉进行最后的调试和测试。具有连续的网络连接，可用于伽马暴余辉的后续观测。

We installed a small automated optical telescope system next to CANGAROO, an array of four imaging Cherenkov telescopes for very-high-energy gamma-ray observation in Woomera, South Australia, in collaboration of Japanese and Australian institutions. The main aim of this project is to monitor time-variable TeV objects, such as active galactic nuclei, and to execute follow-up observations of gamma-ray burst afterglows in optical waveband. Also this telescope can be used to monitor atmospheric condition which is important in Cherenkov observations by observing starlight extinction near the field-of-view of the Cherenkov observations.The system consists of a 30-cm diameter Schmidt-Cassegrain telescope (Meade LX200-30) and a cooled CCD camera (Apogee Ap-7p) controlled by a Linux-based computer via a network. It is equipped with an automated filter wheel with Johnson filters, thus enabling multiwavelength photometry. The observation hut has an automatic roof with use of motors which can be controlled by the computer. For automatic operation it includes various sensors such as a rain monitor which triggers automatic closing of the roof. We developed the software for all of these with help of collaborators. We succeeded in taking some test images with this system. This automated system has been under final tuning and testing in Woomera. With a continuous network connection, it can be used for follow-up observation of gamma-ray burst afterglows.