Software and Hardware to Improve a Remote Telescope Station

Kurzfassung

The telescope network SMARTnet, established and operated by the German Aerospace Center (DLR) in close cooperation with the Astronomical Institute of the University of Bern (AIUB), is conceptualised to collect and distribute data from telescope stations. Contributing stations owned and operated by DLR are running remotely and autonomously. When there is no regular personnel at hand, operational tasks include supervising hardware and software states as well as the environmental conditions. The decision in favour of or against performing observations is made by the software alone and shall be based on well-defined criteria. A decision in favour of observations may be revoked any time in the event of changing conditions. Especially in case of declining weather conditions, observations have to be stopped immediately to prevent hardware damage. Furthermore, the set-up has to be failsafe to shut down observations and station hardware in cases of emergency, e.g. power failures or dome errors. Error handling is thus a key element. If components do not receive or send answers within a reasonable time frame, observations shall be stopped or the error may be solved by the software itself. For DLR’s stations within SMARTnet, the main supervision is based on two computers running in a masterslave configuration. Only the computer in the role of the master is commanding the stations despite of both being individually capable of it. This redundancy is fundamental, and all other hardware components were integrated around this concept. Both computers are checking each other’s reachability via network connection permanently. The computer in the role of the master is checking continuously the status of the station components, the environmental conditions, the observations, and the image processing. The software for controlling the telescope and for processing the acquired images is part of a software package which had already been developed by AIUB. We will show how these software modules are incorporated into the station’s software. Due to DLR’s network security policy, a contact from any stations’ computer to the DLR network is not allowed, disabling possibilities to gain ill-intended access to DLR’s high-security projects. Therefore, a superordinate layer of software monitoring each station was established and is located at DLR. We will primarily focus on the stations’ software and explain the superordinate layer in cases where the communication to the station is involved. In this paper, we will describe adaptations of hardware components and the optimisation of the stations’ software after the start of operation in April 2017. This description will focus on improvements which were made in order to stabilise operations. To put the improvements into context, we will give a condensed overview of the prototype and demonstrator versions, which were already addressed in earlier publications. Subsequently, we will set up scenarios, in which different problems occur after the inauguration in 2017, some hindering observations, some allowing for continuation. We will describe how the system is reacting to ensure maximum safety for the equipment and the steps which are taken to resolve the initially unsolved problems which occured before 2017.