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Characteristics The RoboDIMM itself can be placed in a dome, and consists of a small telescope, a CCD camera and software to control the hardware. The RoboDIMM is controlled by a software package that is running on Linux. It is written entirely in C++, in a multi threaded environment. The object oriented style of the sources make it fairly easy to implement additional device drivers, like CCD drivers and telescope drivers. RoboDIMM can roughly be divided into four parts: a optical telescope, continuously pointed at some predefined bright stars detector: CCD camera, used to monitor the incoming starlight computers and software that control both the telescope and camera and calculates the seeing small clamshell dome to protect the telescope. Hardware description Telescope In theory any 10 or 12 inch telescope can be used, although it must be equipped with a computerized goto-system. Our RoboDIMM is a standard Meade 12 inch LX200. Currently only the LX200-protocol (serial rs232 connection) is supported, but other protocols are easy to implement. For protection the telescope can be placed in a dome. It is polar aligned to minimize possible tracking errors. The optical wedges, mounted in front of the telescope tube, split the incoming light into five separate beams. Hence, five images of the same star are produced, approx. one millimeter separated from each other. The telescope can be equipped with a sensor to protect it from any damage that occurs when the CCD camera is accidentally pushed against the fork. CCD camera The CCD camera is a SBIG ST5C (or a larger version that is software compatible with the ST5C). The ST5-camera has 10 micron square pixels in an array of 320 x 240 pixels (= 3.2 x 2.4 mm). The shortest exposure time is 10 ms, which is good enough to effectively freeze the rapidly changing star images. The exposure time is given by the speed with which atmospheric changes take place. Depending on the circumstances, exposure times in the order of 5-20 ms are needed to freeze these variations. Focuser A JMI focuser is mounted between the telescope and the CCD. The software does automatically focus the telescope system once every hour. Computers and infrastructure The computer that controls the telescope and CCD camera is connected to a network (ethernet); it is equipped with standard Ethernet network interfaces, 100 Mbits/sec; TCP/IP is used as the communication protocol.
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