MMT-AO performances: discussion G. Brusa

Outline Interaction matrix AO system model Calibration issues Performance estimation Tip-tilt error Accelerometer data

Interaction matrix

AO system model DM t CREC WFS s in s off s out

AO Block Diagram WFSC Turbulence Adaptive Secondary WFSIWFSI SSCSSC RTRRTR DMIDMI DDS sposlortrcom, pos, cur

Seeing vs. g’ factor

Best performances H band Seeing 0.4” SR –40% (SE) –20-30% (LE)

Uncorrected tip-tilt 10mas ; Total 30mas (single axis)

Secondary Tilt and Decenter (I) dax = 300 nm rms day = 300 nm rms dlx = 1600 nm rms dly = 300 nm rms da = 15.4 nm/mas dl = 43.1 nm/mas

Secondary Tilt and Decenter (II) dax = 170 nm rms day = 130 nm rms dlx = 310 nm rms dly = 120 nm rms da = 15.4 nm/mas dl = 43.1 nm/mas

Conclusions How are we going to measure the interaction matrix ? Is there an equivalent g’ for the pyramid sensor ? How are we going to setup the diagnostics both from WFC and technical camera ? Do we need to implement a feedforward correction of vibrations ?