Relay optical function and pre-construction results of a Giant Steerable Science Mirror for a thirty meter telescope

The Giant Steerable Science Mirror (GSSM) is the tertiary mirror system of the Thirty Meter Telescope (TMT) that relays optical beams from the secondary mirror to active instruments on Nasmyth platforms. One of the key technologies involved in GSSM functions is the error budget allocation from the system engineering of TMT. A novel approach of error analysis and allocation with strong adaptability, which is based on normalized Point Source Sensitivity (PSSn), is proposed. The relay optical function including the quality of the wavefront, the rationality of the mechanism, and the stability of the light were achieved based on the proposed method. The experiments validate the proposed method.