Design and implementation of the primary and secondary mirror control system for NST

The 1.6-meter New Solar Telescope (NST) will replace the 65 cm reflector that is currently being used at Big Bear Solar Observatory (BBSO). Some technologies new to solar telescopes, including Active Optics, will be employed in NST project. The goal of Active Optics is to correct the low frequency telescope aberrations by adjusting the figure of primary mirror and the position of the secondary mirror. The Active Optics Control Subsystem (AOCS) is part of the Telescope Control System (TCS) for NST. The AOCS will cooperate with the Wavefront Sensing Control Subsystem to correct the lower order aberrations of the telescope system. When fully developed, it will work in close-loop. The wavefront aberration information will be obtained from the wavefront sensor and corresponding corrections will be applied to the primary mirror and the secondary mirror. In this paper, the design and the implementation of the AOCS will be described in detail.