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First Light AO System for LBT: an update

First Light AO System for LBT: an update. SAC Meeting, Bertinoro (BO) , May 3 th , 2002. Personnel and Institutes. S. Esposito, M. Accardo, C. Baffa, V.Biliotti, G. Brusa, M. Carbillet, D. Ferruzzi , L. Fini, I. Foppiani , A. Puglisi, P. Stefanini,

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First Light AO System for LBT: an update

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  1. First Light AO System forLBT: an update SAC Meeting, Bertinoro (BO) , May 3th, 2002

  2. Personnel and Institutes S. Esposito, M. Accardo, C. Baffa, V.Biliotti, G. Brusa, M. Carbillet,D. Ferruzzi , L. Fini,I. Foppiani, A. Puglisi, P. Stefanini, R. Ragazzoni,P. Ranfagni, A. Riccardi, A. Tozzi, C. Verinaud,R. Biasi D. Gallieni, W. Seifert, J.Storm Arcetri Obs. Bologna Obs. Arcetri/Heidelberg MPIA ADS/MicroGate Potsdam/Heidelberg MPIA

  3. The LBT First-Light AO System The DM, Adaptive Secondary (LBT672) The Natural guide star Wavefront Sensor Opto-Mech. The Laser guide star Wavefront Sensor Opto-Mech. Real-Time loop control HW&SW AO System Integration and Testing System Performance Simulations Time schedule Costs & Manpower

  4. Reduce size, number and cost of optical elements • High optical throughput • Minimize NCP aberrations • Reduce system flexure • Reduce turbulence WFS optical path • Easy assembly and testing • the WFS unit • Same HO & TT reference star A Moveable WFS for the AGW unit 20th October 2001 LGS (Sodium) WFS HO small 230x100x100 mm, 110mm refocuseable unit LGS-WFS NGS-WFS NGS WFS HO&TT small 300x400mm,moveable unit acquiring +/- 60 arcsec FOV

  5. LUCIFER Dummy entrance window (15o) F15 beam from LBT LGS (Sodium) WFS HO small 120x100x100 mm, 110mm refocuseable unit NGS WFS HO&TT small 300x400mm, moveable unit acquiring +/- 60 arcsec FOV derotator unit Instrument flange LBT AO System: WFSs 3th may 2002 (Bertinoro)

  6. Optical set-up Tel. PSF Pyramid Optical set-up I

  7. PSF Image plane Pupil plane The Pyramid Operating Principle The pyramid gain Telescope pupil Glass Pyramid . Pupil re-imager 4 3 DETECTOR 1 2 y pixels used for computation of signal Sx and Sy at the corresponding pupil subarea x

  8. NGS WFS XYZ positioning I NGS Positioning Main Requirements • FOV for reference star acquisition • 2x2 arcmin +/- 36mm • Absolute positioning accuracy • 0.1 arcsec, 60 mm • Stability during AO operation, ~ 1 mm, • TBC with 11 mm PSF FWHM @ 750nm • Telecentric lens of 86mm diameter • Overall unit weight ~ 25 kg, • 7.5 Kg optical bench + 15 Kg board • opto-mech.

  9. NGS WFS XYZ positioning II

  10. Gravity direction Mx [Nm] My [Nm] Mz [Nm] X - 86 17 Y 86 - 45 Z 17 45 - Max allowed 100 230 50 XYZ Bending Moments Linear way #1 Overall mass (lumped on the board) = 25 Kg Position = -10 (toward M3), +40 (toward derotator center), -40(toward LGS) FEA Analysis by ADS

  11. Board dimension 400x320 • mm including detectors • 100x100x100 CCD head • 80x100x100 STRAP unit A Moveable WFS for the AGW Unit II Incoming f15 beam from LBT focal plane HO beam TT beam Telecentric lens pyramids Field Viewer beam ADC optics Filter wheel CCD 39/60 Piezo steering mirror PI Field viewer Strap unit

  12. NGS HO Channel NOT TO SCALE

  13. NGS HO Channel 2) LUCIFER Window 3) Telecentric lens 85mm 4) F45 refocusing triplet 5) ADC compensator 6) BS for HO-TT beams separation 7) Fast steering mirror (PI) 9) Refractive double pyramid 10) Camera lens 11) Pupil image plane * Optical Pupil re-rotator Pyramid Edge losses 10 % TOTAL TRASMISSION 0.83 * 0.9 = 75 %

  14. Pyramid and Pupils arrangements • Pupil diameter 720mm (30pixels) • Center to Center pupil distance 864 864mm (36 pixels) • Base angle tolerance: 10 arcsec (1/10pixel) • Thickness tolerance: 100 mm (1/10 pixel) • Vertex u 30.42°, N-BAK4 • Vertex v 29.08°, N-SK16 • FOV +/- 1 arcsec • Energy loss on edges < 10 % • Chromatism 0.9-3 mm at 0-69 deg • wl range (0.6 – 1.0 mm)

  15. HO CCD detector I (EEV39 chip) SciMeasure Analytical Systems, Inc. EEV39 Marconi chip

  16. Ron, dark current, sky backg. Ron only HO CCD detector II (EEV39 chip) 30x30 (bin 1) 15x15 (bin 2) 10x10 (bin 3)

  17. HO CCD detector III (LLL CCD 60) • Two chip sent to Arcetri & Bologna from Marconi. • Control electronic development • in Arcetri: first test September 2002 • Optical test, QE, RON , fps..... at Bologna Obs. • 128x128 pixels • 1 kframe/s • RON < 1 e-

  18. NGS/LGS Tip-Tilt Channel NOT TO SCALE

  19. Pupil image diam. 120 mm Pupil image diam. 120 mm 2.8 mm 2.8 mm NGS/LGS Tip-Tilt Channel II Light from f45 beam +/- 1 arcsec FOV • APD sensitive area 200 mm • APD separation adjustable • around 2.8 mm • Pyramid angle 30 deg (SSK2) • Chromatism about 30 mm

  20. 3L CCD 65 • Sensitive area 11.5x8.6 mm • FOV 6.4x4.8 arcsec • Pixel size 20x30 mm • R band not well sampled Technical/Scientific viewer channel Option for technical viewer: CCD65 camera Detector limited !

  21. HO Pyramid focusing • HO camera lens centering XY • TT Pyramid focusing • TT camera lens centering XY • Fast TT mirror • Filter wheels (2) • ADC rotator • Pupil Re-Rotator On-Board positionings electronics Main On-Board positioning requirements

  22. On Board parts and detectors price list

  23. On Board motorized parts and detectors

  24. Telecentric lens mount, 84mm diam (1) • Sodium Laser Pick-Up mirror (2) • FISBA Calibration interferometer (3) • Interferometer Corner Cube (4) • LUCIFER dummy window (5) Auxiliary Units Main NGS auxiliary units     

  25. Auxiliary units positionings

  26. Auxiliary units mounts EDMUND OPTICS components taken just to perform a system layout study; other brands equivalent components wiil be evaluated before finalizing the mechanical design

  27. NGS WFS Unit Laser pick-up HO NGS WFS BOARD LBT f15 beam TT SW telecentric lens mount Mirror for LGS WFS Light feeding LUCIFER dummy window FISBA Fizeau interferometer BS for NGS WFS calibration

  28. Opto-Mechanical tolerances Pupil displacements rate in mm/mm or mm/arcsec Folding mirror Camera lens NGS board Lucifer window Refocusing triplet Pyramid tilt Pyramid polishing Telecentric lens

  29. LGS WFS unit • Zenit angle range 0-70deg • WFS translation of 110mm • Laser dichroic insertion • Max sub. No. 30x30 • NGS board used for TT sensing Sodium Laser WFS unit F15 beam from LBT Laser dichroic NGS WFS

  30. LGS WFS Channel NOT TO SCALE

  31. LGS WFS unit LUCIFER window 210mm Laser Dichroic 210mm Focusing 110mm for Zenith angle 0—70 deg 720mm 864mm 12 mm 10 mm 4mm

  32. Laser WFS Unit NGS WFS unit NGS & LGS unit inside derotator FEA Analysis by ADS

  33. NGS&LGS with crates II

  34. NGS Sistem Performance Simulations I • Atmospheric turbulence: 2 layers, wind vel.=15m/s,r0(@500nn)=0.15m (l/r0=0.67arcsec), Lo=40m; • Guide Star K5, Vmag 9.85—17.5; • Telescope: 8.25m diameter, obstructio ratio 0.11; • Pyramid Wavefront Sensor: tilt modulation 2,3 l/D • Reconstructor: 10x10sub 44,55, 66 LBT672 modes, 15x15sub: 78,105,136 LBT672 modes; 30x30sub: • 231, 351, 496 LBT672 modes; time filtering: pure integrator (gain=0.5)

  35. NGS Sistem Performance Simulations II NAOS@VLT UT4 Hokupaha@Gemini South • Atmospheric turbulence: 7 layers, wind vel.=7--34m/s, • r0(@500nn)=0.166, (l/r0=0.62 arcsec); • Guide Star: mag 10--18; • Telescope: 7.9m diameter, obstructio ratio 0.13; • Curvature Wavefront Sensor • Atmospheric seeing 0.65 arcsec; • Guide Star: G0V, Vmag 10--18; • Telescope: 7.9m diameter, obstructio ratio 0.13; • Shack-Hartmann Wavefront Sensor: 7x7, 14x14

  36. General Schedule PDR

  37. WFS&CL Overwiev table

  38. Board Opto-mech. & SW

  39. NGS WFS OptoMech. & SW

  40. Conclusion The Natural guide star Wavefront Sensor Opto-Mech. The Laser guide star Wavefront Sensor Opto-Mech. System Performance Simulations Opto-Mech.& Detectors costs

  41. NGS 3 positioning stages

  42. Simulation SR table

  43. NGS HO beam Optical Tolerances Pupil displacements rate in mm/mm or mm/arcsec Folding mirror Camera doublet Refocusing triplet Lucifer window NGS board Telecentric lens Pyramid tilt

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