1. Temporal Error Minimization In Adaptive Optics Control Loop
Mark Nishimura
Internship Site: Subaru Telescope (NAOJ)
Mentor: Olivier Guyon

2. Outline
Subaru Adaptive Optics
Error Minimization
Results

3. Subaru AO System Next Generation AO System Three elements:
Wave-Front Sensor
Curvature Sensor
Control Computer
Deformable Mirror
Bimorph Mirror

4. Adaptive Optics Simulation
Created in C one actuator simulation of AO system
Realistic Simulated Atmosphere

5. Adaptive Optics Simulation
Photon Noise
Time Delay (125 micro sec)
DM Response

6. Project Test new ideas to improve performance
Increasing DM update frequency
Average the number of photons in time
Smith Compensator

7. DM Updates Send updates twice as often to DM Limitation
Frequency of Vibrating Membrane

8. Average Photon Count I(+)-I(-) / I(+)+I(-) = Curvature
I(+)-I(-) / I(ave)+I(ave) = Curvature
Decreases the effect of photon noise
Results
Improvements with guide stars dimmer than Magnitude 9

9. Smith Compensator (Predictor)
Prevents over correction due to delay
DM Position
DM Signal

10. Results
Significant improvements below 80Hz
Limitations
DM Response

11. Future Improvements
Find a clever way to drive DM to limit oscillations

12. Acknowledgments Subaru Telescope (NAOJ) Olivier Guyon Hideki Takami
This project is supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST