Software control and characterization aspects for image derotator of the AO188 system at Subaru
The image derotator is an integral part of the AO188 System at Subaru Telescope. In this article software control, characterization and integration issues of the image derotator for AO188 System presented. Physical limitations of the current hardware reviewed. Image derotator synchronization, tracking accuracy, and problem solving strategies to achieve requirements presented. It's use in different observation modes for various instruments and interaction with the telescope control system provides status and control functionality. We describe available observation modes along with integration issues. Technical solutions with results of the image derotator performance presented. Further improvements and control software for on-sky observations discussed based on the results obtained during engineering observations. An overview of the requirements, the final control method, and the structure of its control software is shown. Control limitations and accepted solutions that might be useful for development of other instrument's image derotators presented.