A Pyramid WFS For LBT AGW UnitA 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

Scientific Aim........Scientific Aim........

Answering a first fundamental question:

“ Whould you let those guys....[J. Hill, e-mail, 16 October 2001]

....project your AO system ? ”

A Moveable WFS for the AGW unitA 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

The Optical Design IThe Optical Design I

pupil 8.3 mm

The Optical Design IIThe Optical Design II

Telecentric lens

Refocusing lensand folding mirror

Pyramid unit

2 Folding mirrors

ADC & Tip-Tilt mirror

Reimaging lens

F15 beam from LBT

117 mm

294 mm

Spot quality on the pyramid ISpot quality on the pyramid I

ON Axis Spot 1’ OFF Axis Spot

Zenith pointing

Spot quality on the pyramid IISpot quality on the pyramid II

ON Axis Spot 1’ OFF Axis Spot

70 deg from Zenith pointing

The Pyramid design IThe Pyramid design I

Light direction

1 arcsec off-axis beam 10 mm

•Vertex 30°, SK10•Vertex 28.2°, SSK2•FOV +/- 1 arcsec•Energy loss on edges < 10 %•Chromatism 3.5 m (0.6 – 1.0 m)

The Pyramid design IIThe Pyramid design II

76 pixel 1828 micron

X Y

34 pixel 814 micron

7 pixel 174 micron

Pyramid edges orientation

EEV39 sensitive surface

The board assemblyThe board assembly

Telecentric lens

ADC and TT mirror

Folding mirrors

Re-imaging lens

Pyramid

CCD box

The APD-based TIP-TILT systemThe APD-based TIP-TILT system

Work in progress……Work in progress……

Optical design & Pyramid design optimization

Optical & echanical tolerances

echanical design

System performance simulations

other................