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CANARY

CANARY. On-sky results from the first tomographic MOAO demonstrator. Tim Morris Centre for Advanced Instrumentation, University of D urham. Introduction. MOAO description MOAO on the E-ELT CANARY Phase A System calibration On-sky results CANARY Phase B. What is MOAO?.

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CANARY

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  1. CANARY On-sky results from the first tomographic MOAO demonstrator Tim Morris Centre for Advanced Instrumentation, University of Durham

  2. Introduction • MOAO description • MOAO on the E-ELT • CANARY Phase A • System calibration • On-sky results • CANARY Phase B

  3. What is MOAO? • Multiple Object Adaptive Optics • A technique for extending Adaptive Optics correction to multiple objects distributed within a very wide field of regard • Planned operating mode for several facility class instruments: • RAVEN on Subaru • CONDOR on the VLT • Keck NGAO • NFIRAOS on TMT • EAGLE on the E-ELT

  4. Why are we trying to do it? 10’ Technical 5’ Science SCAO/LTAO/XAO MCAO GLAO MOAO E-ELT focal plane

  5. How does MOAO work? Atmospheric Turbulence Atmospheric Turbulence Telescope Pupil WFS 1 WFS 2 Science Camera

  6. How does MOAO work? WFS 1 WFS 2 Science Camera

  7. How does MOAO work? • Tomographic Wavefront Sensing

  8. How does MOAO work? • Tomographic Wavefront Sensing

  9. How does MOAO work? • Tomographic Wavefront Sensing

  10. How does MOAO work? • Closed-loop wavefront control (MCAO) Aberrated Wavefront Deformable Mirror(s) Corrected Wavefront WFSs Science Camera/IFU Wide field of view allows the WFSs to be positioned behind the DM

  11. How does MOAO work? • Closed-loop wavefront control (MCAO) Aberrated Wavefront Deformable Mirror(s) Corrected Wavefront WFSs Science Camera/IFU Optimal correction FOV of an MCAO system

  12. How does MOAO work? • Open-loop wavefront control (MOAO) Aberrated Wavefront WFSs Deformable Mirror(s) Corrected Wavefront WFS and science paths are separated. WFSs cannot observe the AO correction Science Camera/IFU

  13. MOAO for the E-ELT: EAGLE • EAGLE is a proposed MOAO IFU spectrograph for the E-ELT • 20 IFU channels with a 1.6” FOV and 35mas sampling • EAGLE will provide ≥30% EE within 70mas at 1.6µm • Two modes providing R=4000 & 10000 Phase A EAGLE design installed in the GIFS of the E-ELT

  14. Why choose MOAO for EAGLE? • LTAO/SCAO • Excellent correction • Too slow to perform surveys with only a single IFU • MCAO • Very good correction • Too many DMs required to reach performance requirements over full FOV • GLAO • Very wide field, minimal correction • Performance is low and highly dependent on turbulence profile • MOAO • Distributed open-loop AO with integrated multi-IFU system • One DM per target field means optimal correction along every line of sight • Performance and sky coverage means LGS

  15. EAGLE science case(s) • 5 main science cases: • The evolution of distant galaxies • Detection and characterisation of first-light galaxies at the highest redshifts • The physics of galaxy evolution from stellar archaeology • Star-formation, clusters, and the initial mass function • Co-ordinated growth of black holes and galaxies in the local and distant Universe • Many more auxiliary science cases • All benefit from the multiplex over observing 20 patches of sky at once...

  16. 9 arcsec 1.6’’ x 1.6’’ I = 22.5 S/N=43 & 36 I = 23.1 S/N=23 ACS image I = 22.8 S/N=28 EAGLE: 1000 stars in ~ 25 hrs Simulated EAGLE cube ACS image

  17. Why do we need an MOAO demonstrator? • VOLT 1 and ViLLaGEs 2 have both demonstrated open-loop AO on-sky • Tomographic MOAO had never been demonstrated on-sky • Neither NGS or LGS tomography • Several questions left to answer for MOAO & EAGLE: • Accuracy of tomographic wavefront sensing and reconstruction • Open-loop DM control • Required calibration and alignment procedures • Closed-loop woofer/open-loop tweeter DM configuration • Sensitivity to changing turbulence profiles • … 1 Andersen et al, Proc SPIE 7015, 70150H (2008) 2 Morzinski et al, Proc SPIE 7736, 77361O (2010)

  18. CANARY Project • Create a single MOAO channel EAGLE as closely as possibly using the 4.2m William Herschel Telescope • Effectively a 1/10th scale model of E-ELT using a 10km Rayleigh LGS • Perform NGS, then LGS based tomographic WFSing • Perform open-loop AO correction on-sky • Develop calibration and alignment techniques • Fully characterise system and subsystem performance • No requirement to perform astronomical science…

  19. Phase A: NGS MOAO Science Verification NGS FSM Low-order DM NGS Pickoffs WHT Nasmyth GHRIL Derotator Truth Sensor Figure Sensor Calibration Unit 3 x NGS WFS Phase A : NGS MOAO • Components: • Low-order 8x8 DM • 3 x L3CCD open-loop NGS WFSs • Open-loop optimised Fast Steering Mirror • Hardware accelerated Real Time control system • NGS MOAO Calibration Unit 10" science FOV NGS WFS NGS WFS NGS WFS 2.5’ Derotated WHT field CANARY: An LGS MOAO demonstrator

  20. Optical layout Telescope Simulator not shown, but it feeds in here

  21. CANARY at the WHT

  22. Open-loop WFSs

  23. Instrument Architecture

  24. Real Time Control System • PC based • Runs as a multi-threaded high priority process • Compatible with real-time Linux • Modular design • Shared memory telemetry interface • System controlled via CORBA object • Updates at ~1.2kHz with CPU pixel processing • ~5kHz with FPGA pixel processing • Measured latency of 0.8ms • Robust operation • Open-source…

  25. System calibration • CANARY contains over 20 calibration and alignment sources 1 x on-axis VIS SL source 1 x on-axis reverse path source 1 x on-axis NIR DL source 1 x on-axis VIS SL source 1 x on-axis VIS DL source 1 x off-axis source for figure sensor 4 x off-axis VIS SL sources 4 x off-axis VIS DL sources 1 x on-axis VIS SL source 1 x on-axis VIS DL source 1 x on-axis NIR DL source 1 x on-axis alignment laser 1 x on-axis pupil alignment laser 1 x on-axis pupil pinhole source

  26. Reverse path calibration • Open-loop WFSs measure the DM response by looking backwards through the AO system • The reverse-path interaction matrices contain all NGS WFS – DM registration information WFS AO PATH Output Focal Plane Input Focal Plane

  27. Tomographic Calibration • Learn and Apply calibration procedure • Record 10-30s of on-sky wavefront data from the on- and off-axis WFSs • Calculate a turbulence profile from this data • Calculate covariance matrices between off-axis WFSs using the fitted profile and asterism parameters • Calculate covariance matrices between on and off-axis WFS • Additional steps to remove static telescope aberrations, errors due to telescope tracking updates, pupil conjugation, rotations etc. • 4 LGS and 2 NGS Phase B LGS example…

  28. LGS//NGS_TT TS//NGS NGS_TT//NGS LGS//NGS HO + TT NGS//NGS -1 Mt = x COnOff COffOff NGS//NGS_TT TS//NGS_TT TT only high order TS//LGS NGS_TT //LGS NGS//LGS -1 NGS_TT//NGS_TT LGS//LGS = x

  29. Tomographic command Matrix TS Control matrix Mct = Mt x (Measured in lab) x 72 = 72x6 72x6 +2 52 54 72

  30. Results • 8 nights allocated on the WHT • 4 in September 2010, 4 in November • 6 nights lost to bad weather! • 3 asterisms observed

  31. Results: Example • Initial results only • Much more analysis required to fully understand the system • H-band • 2 x 2” FOV • 30s exposures seeing ≈3% GLAO 13% SCAO 27% MOAO 25%

  32. Results from night Sept. 27-28 SCAO = ▲ MOAO = ◯ GLAO = ◻

  33. Performance vs r0 (as Feb2011) from night Sept. 27-28 SCAO = ▲ MOAO = ◯ GLAO = ◻

  34. Results • Sometimes there is little difference between GLAO and MOAO • Some of the performance variation is due to parameter tuning within the RTCS (gain, thresholds etc.) • The small aperture of the WHT limits CANARY tomography to altitudes below ~6km • Precise value dependent on asterism parameters and reconstruction • Tomography would work better on a larger telescope • Increase in pupil diameter from 4m to 8m will push performance closer to SCAO levels • LGS are necessary to get sky coverage anyway

  35. Performance (as Feb2011) Pessimistic approximation SR=exp(-σ2) from night Sept. 27-28 SCAO = ▲ MOAO = ◯ GLAO = ◻

  36. Phase A questions • Performance at the lowest spatial frequencies does not match theory • Similar characteristics observed with both VOLT and ViLLaGEs • Several possible explanations still under investigation • Best optical performance of the system is ~70% in the H-band • DM surface exhibits high-frequency polishing errors? • Throughput to NGS WFSs is lower than expected • Issue with the frame transfer?

  37. CANARY firsts on-sky... • Tomographic MOAO demonstration • Open-loop GLAO demonstration • MMSE Tomographicreconstructor • Learn & Applytomographic calibration • Additionaldemonstrations: • New Shack-Hartmann WFSingalgorithms: • Brightest pixel centroiding, adaptive windowing, correlation (and more) • New type of polarisation based WFS (YAW/ADONF) • On-skymeasurement of interaction matrices • CPU-based (Linux) Real Time Control system • FPGA and GPU RTC acceleration

  38. Phase B: Low-order LGS MOAO Figure Sensor 3 x NGS WFS GLAS BLT Diffractive Optic LGS Rotator GLAS Laser • Adds four open-loop LGS WFSs to the existing three NGS WFSs • Can run in LGS or NGS modes or a mixture of both • Crucial for demonstrating EAGLE NGS Pickoffs NGS FSM Low-order DM LGS Dichroic WHT Nasmyth GHRIL Derotator LGS Pickoffs 1.0’ Diameter LGS asterism Truth Sensor Science Verification Calibration Unit LGS FSM Phase B: Low-order LGS MOAO 4 x LGS WFS LGS WFS

  39. Phase A We have done this at Phase A: copy of the full focal plane NGS wfs Adonis DM telescope rotater camera relay optics NGS wfs focal plane The relay optics are designed to transport the full 3’ diameter FOV – required for Phase C Only the central 10’’ is actually used by the camera

  40. dichro LGS wfs Phase B We planned to do this: NGS wfs Adonis DM telescope rotater camera relay optics NGS wfs

  41. dichro LGS wfs Phase B But ended up designing this so we could fall back to Phase A: NGS wfs Adonis DM telescope rotater camera relay optics NGS wfs This layout is complicated by the crowded focal plane.....

  42. Finding room on the bench • LGS beam separated dichroically before NGS WFSs • LGS WFS positioned on raised bench • MIT/LL CCID-18 electronically gated CCD • LGS Tip/tilt mirror to correct for LGS launch jitter

  43. LGS WFS for Phase B • Only have a single detector and we need to place 4 SH WFS patterns on it • Designed a pyramid prism to allow us to vary LGS asterism altitude and spacing

  44. Changingthe LGS asterism Change the asterism diameter Change the asterism altitude • Altitude range: 11 km to 25 km • Asterism range: LGS diagonal on sky between 3.2 m and 3.8 m

  45. Laser Launch System Laser enclosure mounted at the top-ring of the telescope 2 x 16W lasers are combined and then sent through a DOE to create the 4 LGS asterism Interfaces to existing WHT beam-launch optics

  46. Phase B timeline • Multi-LGS system being commissioned in July/November • Phase B CANARY being commissioned in Paris • On-sky date for full Phase B system of May 2012 CANARY lasers during acceptance testing at Durham (2010) WHT Rayleigh LGS, GLAS, being launched during 2008 Image of 4 LGS asterism taken during testing in 2008

  47. Summary • MOAO is a powerful technique for extending high accuracy AO correction to points distributed over a very wide field • CANARY has demonstrated fully tomographic NGS MOAO on-sky • Tomographic reconstruction achieved significant improvement over GLAO, and approached SCAO levels of performance • Initial results promising, but more work is required to fully understand results • LGS upgrade is progressing and will be commissioned in July • It has been a very easy to integrate and test new hardware and software modules into CANARY in addition to demonstrating MOAO

  48. The CANARY team • The CANARY project is supported via the following funding bodies • STFC • UK E-ELT Design Study • EU FP7 Preparatory fund WP9000 • ANR Mauii, INSU, Observatoire de Paris • FP7 OPTICON JRA1 CANARY: NGS/LGS MOAO demonstrator

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