1. Active Control of Aberrations for the Large Synoptic Survey Telescope (LSST) Brice Cannon Lawrence Livermore National Laboratory Research Supervisor: Scot Olivier Research Mentor: Stacie Hvisc Home Institution: Norfolk State University

2. Outline LSST LSST Basic Design Basic Design Curvature Sensors Curvature Sensors Results Results Conclusion Conclusion

3. 3 Mirrors 3 Mirrors 10 square-degree field 10 square-degree field 3.2 Gigapixel camera 3.2 Gigapixel camera Google Universe? Google Universe? Chile Chile

4. Basic Design M1 8.4m M2 3.4m M3 5.0m Camera Focal Plane CWFS

5. Camera: Focal Plane Array d Bay 17Bay 16Bay 15Bay 18Bay 19 Bay 22Bay 21Bay 20Bay 23Bay 24 Bay 12Bay 11Bay 10Bay 13Bay 14 Bay 17Bay 16Bay 15Bay 18Bay 19 Bay 07Bay 06Bay 05Bay 08Bay 09 Bay 02Bay 01Bay 00Bay 03Bay 04 42 mm CWFSFocal Plane d d

6. Active Control of Aberrations Mirror aberrations Mirror aberrations Gravity and thermal changes Gravity and thermal changes Curvature sensor errors Curvature sensor errors Sky-brightness Sky-brightness Phase reconstruction Phase reconstruction

8. Effect of Sky-Brightness

9. Applied Phase Reconstructed phase diagram from CCD Intra focus CCD Image Extra focus CCD Image Stellar Magnitude 19 18 17 16 15 14

10. RMS CWFS error vs. Stellar Mag.

11. Probability

12. All bands at 90

13. 90 vs. 30

14. Conclusion Sky-brightness will introduce error Sky-brightness will introduce error Simulated LSST CWFS accuracy meets requirements Simulated LSST CWFS accuracy meets requirements Promising performance capabilities Promising performance capabilities Future Design improvements Future Design improvements Implementation in a LSST model Implementation in a LSST model

15. Acknowledgements Scot Olivier Stacie Hvisc Don Phillion Kevin Baker CfAO "Funding provided through the Center for Adaptive Optics, a National Science Foundation Science and Technology Center (STC), AST-987683."

16. References Krisciunas, Kevin, and Bradley E. Schaefer. "A Model of the Brightness of Moonlight." Astronomical Society of the Pacific 103(1991): 1033-1039. Krisciunas, Kevin, and Bradley E. Schaefer. "A Model of the Brightness of Moonlight." Astronomical Society of the Pacific 103(1991): 1033-1039. LSST, "LSST: A New Telescope Concept." Large Synoptic Survey Telescope. January 2007. LSST Corporation. 11 Jul 2007. LSST, "LSST: A New Telescope Concept." Large Synoptic Survey Telescope. January 2007. LSST Corporation. 11 Jul 2007. Phillion, Donald, Scot S. Olivier, Kevin Baker, and Stacie Hvisc. "Tomographic wavefront correction for the LSST." Advances in Adaptive Optics II,. 6272(2006): 1-12. Phillion, Donald, Scot S. Olivier, Kevin Baker, Lynn Seppala,and Stacie Hvisc. "Tomographic wavefront correction for the LSST." Advances in Adaptive Optics II,. 6272(2006): 1-12.