1. AO for ELT – Paris, 22-26 June 2009 MAORY Multi conjugate Adaptive Optics RelaY for the E-ELT Emiliano Diolaiti (INAF–Osservatorio Astronomico di Bologna) On behalf of the MAORY Consortium http://www.bo.astro.it/~maory INAF + University of Bologna ONERA ESO

2. AO for ELT – Paris, 22-26 June 2009 2 Concept  Corrected field of view –Central 53"x53" unvignetted for MICADO –Outer field Ø=160" for Natural Guide Star search and other instruments  Wavefront sensing –6 Sodium Laser Guide Stars for high-order wavefront measurement –3 Natural Guide Stars for low-order and windshake measurement –1 Natural Guide Star used as high-order reference WFS  Wavefront correction –Telescope M4 + M5 –2 post-focal deformable mirrors –Simplified option with 1 post-focal DM and reduced outer field under study

3. AO for ELT – Paris, 22-26 June 2009 3 Two ports 1) gravity invariant w/ field derotation 2) vertical w/o field derotation Preliminary bench size: 6335 mm  6755 mm Preliminary mass estimate: 13 t See poster by Italo Foppiani

4. AO for ELT – Paris, 22-26 June 2009 4 Optical design M7 R = 10 m K = -0.87 D = 1 m M9 R = 9.8 m K = -0.91 D = 1.1 m M11 R = 9,.8 m K = -0.91 D = 0.9 m M13 R = 10 m K = -0.87 D = 0.9 m M13 R = 10 m K = -0.87 D = 0.9 m M8 DM @4km D = 370 ~45 act/D M10 Flat D = 0.9 m M12 DM @12.7km D = 414 mm ~52 act./D Field Ø160" WFE  25 nm Distortion < 0.1% Field curvature R = 1.3m To LGS channel

5. AO for ELT – Paris, 22-26 June 2009 5 LGS optics and aberrations Dichroic L1 D = 800 mm L2 D = 700 mm L3 D = 580 mm L4 D = 460 mm 200 km80 km 350 mm  Design features –All lenses made of BK7, spherical surfaces (with wedge) –Output focus F/5, telecentric  Image quality –LGS spot FWHM  0.17 arcsec (LGS image through atmosphere  1.5 arcsec) –RMS WFE  2.6 (average for 6 LGS)  SH WFS slope offset  0.5 arcsec  Solutions to LGS aberrations –Correcting optics (likely not static) in each LGS probe –Handled as slope offset  Pupil stabilization and jitter control to be implemented in each LGS probe

6. AO for ELT – Paris, 22-26 June 2009 6 Thermal emission Telescope emissivity = 10% Sky brightness K = 13 mag/arcsec 2 Emissivity of MAORY optics = 1% per surface (left) or 2% per surface (right) No cooling for T < 30  CNo cooling for T < 16  C Requirement on thermal emission < 50% (telescope + sky) @ K Requirement seems to be fulfilled at ambient temperature Paranal average temperature year 2003 (highest average 1985-2006): T = (13.1  2.6)  C (from http://www.eso.org/gen-fac/pubs/astclim/paranal/temperature/)

7. AO for ELT – Paris, 22-26 June 2009 7 Pupil rotations  Baseline –LGS fixed wrt telescope –Post-focal DMs derotated by 60° (  30°) –LGS WFS probes derotated by 60° (  30°)  How do things move in this scheme? –All DMs (M4 and post-focal) appear fixed wrt LGS WFS –Pupil rotates wrt post-focal NGS WFS at maximum speed ~15/s for a Zenith angle of 1°. Reconstruction matrix of low order modal loop to be updated every 10s –High order loop reconstruction matrix (25GB of data) must be updated every 140s (LGS footprint variation)  Alternatives –Post-focal DMs cannot be derotated  reconstruction matrix to be updated every 35s –LGS fixed wrt sky  reconstruction matrix to be updated every 0.5s

8. AO for ELT – Paris, 22-26 June 2009 8 LGS Wavefront Sensor 0.75 "/pixel 1.0 "/pixel 1.5 "/pixel Weighted Center of Gravity Photons / subap = 500, RON = 3 Subaperture FoV = 15"  15" 0.75 "/pixel 1.0 "/pixel 1.5 "/pixel Non linearity WCoG vs. Quad-cell  Evaluation of algorithms performance for SH WFS –WFS noise –Impact of Sodium profile –LGS aberrations  Alternative WFS –Pyramid (smaller detectors) –Dynamic refocus (by segmented mirrors on sub-pupils?) Poster by Matteo Lombini

9. AO for ELT – Paris, 22-26 June 2009 9 Focus reconstruction scheme Sodium focus sequence on 42 m aperture  Requires NGS reference 6 LGS measure atmospheric + Sodium focus  Used to “predict” focus in direction of NGS  Comparison of predicted NGS focus with actual focus gives Sodium term F(θ 1 ) + Na F(θ 2 ) + Na F(θ 3 ) + Na F(θ 4 ) + Na F(θ 5 ) + Na F(θ 6 ) + Na F(θ)

10. AO for ELT – Paris, 22-26 June 2009 10 NGS Wavefront Sensor Target WFE = 100 nm (3 NGS)  4 mas residual jitter per NGS NGS measured in IR benefit from high-order loop correction Baseline H band Windshake is the most challenging issue for tip-tilt. After feedback on telescope main axes a residual jitter ~0.3 RMS is expected. Making use of a predictive control filter (like Kalman) it may be drastically reduced exploiting its high temporal correlation (low frequency components) 4-5 mas/pixel, 1"  1" FoV  at least 256  256 pixels detector required. This is 2  the foreseen high speed IR sensor by Teledyne (128  128, 5e - RON @900Hz, J. Beletic, SPIE 2008 Marseille) T = 5 ms

11. AO for ELT – Paris, 22-26 June 2009 11 MCAO tomography WFS1WFS2WFS3 More details by Jean-Marc Conan and Clélia Robert  Tomography performed by –6 LGS, launched from M1 edge, kept fixed with telescope to relax requirements on RTC. LGS FoV = 2' –3 NGS for low-orders reconstruction  Star oriented architecture

12. AO for ELT – Paris, 22-26 June 2009 12 Error sources ItemRMS WFE MCAO (High order)255 nm Generalized fitting + tomography232 nm LGS WFS noise77 nm Generalized aliasing41 nm Temporal error60 nm NGS WFS100 nm NGS WFS noise and time delay100 nm Implementation errors140 nm Optics (including non-common path errors) Deformable mirrors AO control Sodium layer Atmosphere TOTAL308 nm Current PSF estimates include MCAO error budget Other error sources included in Strehl Ratio and Encircled Energy End-to-end simulations ready soon Estimated by “Fourier” code + cone effect degradation factor Input to NGS WFS design and sky coverage estimation Top level allocations More details on simulations by Cyril Petit

13. AO for ELT – Paris, 22-26 June 2009 13 Strehl Ratio NGS search field

14. AO for ELT – Paris, 22-26 June 2009 14 Encircled Energy (0.8" seeing) 500 mas 200 mas 75 mas 50 mas

15. AO for ELT – Paris, 22-26 June 2009 15 Performance & Sky coverage Seeing @0.5 µm Strehl Ratio % K s (2.16 µm) H (1.65 µm) J (1.215 µm) Y (1.021 µm) I (0.9 µm) 0.8"53.133.813.66.02.7 0.6"60.742.520.710.75.7 Nominal average performance over MICADO field of view (53"  53") Seeing @0.5 µm Minimum field-averaged Strehl RatioProbability K s (2.16 µm) H (1.65 µm) J (1.215 µm) Y (1.021 µm) I (0.9 µm) 0.8"53.133.813.66.02.726% 47.828.29.73.71.538% 41.221.96.11.90.648% 0.6"60.742.520.710.75.733% 54.635.414.86.63.148% 47.127.59.33.41.357% Sky coverage at North Galactic Pole (L 0 = 25m, windshake included) 3 NGS (2 Tip-Tilt, 1 Tip-Tilt & Focus) measured at H band, NGS search field Ø = 2.5‘ Sky cov. estimated by Monte Carlo simulations of asterisms based on TRILEGAL code

16. AO for ELT – Paris, 22-26 June 2009 16 PSF modeling for scientific analysis  AiryHexagonal MoffatMoffat Simulated PSF DIFFRACTIONFITTING ERRORS, UNSEEN MODESSEEING Model components PSF model Strehl Ratio  0.6 Image size = 2.7"

17. AO for ELT – Paris, 22-26 June 2009 17 Acknlowledgment The activities outlined in this talk were partially funded by the European Community under the following grants: –Framework Programme 6, ELT Design Study, contract No 011863 –Framework Programme 7, Preparing for the Construction of the European Extremely Large Telescope, contract No INFRA- 2007-2.2.1.28