Active optics and control architecture for a Giant Segmented Mirror Telescope

The next generation 30-meter class ground-based telescopes pose an unprecedented challenge for control systems envisioned to support diffraction limited imaging. Our approach is a multi-tiered, decentralized control architecture utilizing two kinds of feedback: optical and mechanical. Based on simulations, we suggest a configuration where the optical feedback loops for the main axes, secondary mirror rigid body motions and segmented primary mirror are separated in both temporal and spatial frequency domains. The active optics system maintaining the continuity and higher order shape of the primary mirror is based on mechanical sensors while the low order shape is corrected through optical feedback. Shown are the results of numerical simulations using real, measured wind data that prove the feasibility of the suggested architecture.