2. A Pyramid WFS For LBT AGW Unit S. Esposito, A. Riccardi, D. Ferruzzi, A. Tozzi, M. Accardo, M. Carbillet, C. Verinaud, L. Fini, A. Puglisi, P. Salinari

3. Scientific Aim........ Answering a first fundamental question: “ Whould you let those guys.... [J. Hill, e-mail, 16 October 2001]....project your AO system ? ”

4. A Moveable WFS for the AGW unit Reduce the number of optical elements Minimize NCP aberrations Minimize system flexure Easy assembly and testing of the WFS unit

5. The Optical Design I

6. The Optical Design II Telecentric lens Refocusing lens and folding mirror Pyramid unit 2 Folding mirrors ADC & Tip-Tilt mirror Reimaging lens F15 beam from LBT 117 mm 294 mm

7. Spot quality on the pyramid I ON Axis Spot1’ OFF Axis Spot Zenith pointing

8. Spot quality on the pyramid II ON Axis Spot1’ OFF Axis Spot 70 deg from Zenith pointing

9. The Pyramid design I Vertex  30°, SK10 Vertex  28.2°, SSK2 FOV +/- 1 arcsec Energy loss on edges < 10 % Chromatism 3.5  m (0.6 – 1.0  m) 

10. The Pyramid design II

11. The board assembly

12. The APD-based TIP-TILT system

13. Work in progress…… Optical design & Pyramid design optimization Optical &  echanical tolerances  echanical design System performance simulations other................