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MOAO description MOAO on the E-ELT CANARY Phase A System calibration On-sky results CANARY Phase B
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M ultiple O bject A daptive O ptics 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
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10’ Technical 5’ Science SCAO/LTAO/XAO MCAO GLAO MOAO E-ELT focal plane
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S CIENCE C AMERA WFS 2WFS 1 A TMOSPHERIC T URBULENCE T ELESCOPE P UPIL
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S CIENCE C AMERA WFS 2WFS 1
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Tomographic Wavefront Sensing
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Closed-loop wavefront control (MCAO) Wide field of view allows the WFSs to be positioned behind the DM A BERRATED W AVEFRONT D EFORMABLE M IRROR ( S ) WFS S C ORRECTED W AVEFRONT S CIENCE C AMERA /IFU
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Closed-loop wavefront control (MCAO) Optimal correction FOV of an MCAO system A BERRATED W AVEFRONT D EFORMABLE M IRROR ( S ) WFS S C ORRECTED W AVEFRONT S CIENCE C AMERA /IFU
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Open-loop wavefront control (MOAO) WFS and science paths are separated. WFSs cannot observe the AO correction A BERRATED W AVEFRONT D EFORMABLE M IRROR ( S ) WFS S C ORRECTED W AVEFRONT S CIENCE C AMERA /IFU
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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
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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
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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...
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9 arcsec ACS image Simulated EAGLE cube I = 22.5 S/N=43 & 36 I = 23.1 S/N=23 I = 22.8 S/N=28 EAGLE: 1000 stars in ~ 25 hrs 1.6’’ x 1.6’’
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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)
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Create a single MOAO channel EAGLE as closely as possibly using the 4.2m William Herschel Telescope Effectively a 1/10 th 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…
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13 th October 2009 CANARY: An LGS MOAO demonstrator 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 WHT Nasmyth Calibration Unit NGS Pickoffs 3 x NGS WFS NGS FSM Low-order DM Science Verification Truth Sensor Figure Sensor GHRIL Derotator Phase A: NGS MOAO NGS WFS 10" science FOV 2.5’ Derotated WHT field
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Telescope Simulator not shown, but it feeds in here
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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…
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CANARY contains over 20 calibration and alignment sources 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 laser1 x on-axis pupil alignment laser1 x on-axis pupil pinhole source1 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 1 x on-axis VIS SL source 1 x on-axis reverse path source
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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 AO PATH WFS Input Focal Plane Output Focal Plane
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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…
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LGS//LGSLGS//NGS_TT NGS_TT //LGS NGS_TT/ /NGS_TT LGS//NGSNGS//LGS NGS//N GS NGS//N GS_TT NGS_TT/ /NGS C OffOff C OnOff x = Mt = x TS// LGS TS//N GS_TT TS//N GS high order TT only HO + TT
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52 72 72x6 72 +2 Mt TS Control matrix x x = Mct (Measured in lab) = 54 72x6
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8 nights allocated on the WHT 4 in September 2010, 4 in November 6 nights lost to bad weather! 3 asterisms observed
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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%
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from night Sept. 27-28 SCAO = ▲ MOAO = ◯ GLAO =
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from night Sept. 27-28 SCAO = ▲ MOAO = ◯ GLAO =
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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
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from night Sept. 27-28 Pessimistic approximation SR=exp(-σ 2 ) SCAO = ▲ MOAO = ◯ GLAO =
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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?
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Tomographic MOAO demonstration Open-loop GLAO demonstration MMSE Tomographic reconstructor Learn & Apply tomographic calibration Additional demonstrations: New Shack-Hartmann WFSing algorithms: Brightest pixel centroiding, adaptive windowing, correlation (and more) New type of polarisation based WFS (YAW/ADONF) On-sky measurement of interaction matrices CPU-based (Linux) Real Time Control system FPGA and GPU RTC acceleration
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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 WHT Nasmyth Calibration Unit NGS Pickoffs 3 x NGS WFS NGS FSM Low-order DM Science Verification Truth Sensor LGS Pickoffs 4 x LGS WFS GHRIL Derotator Figure Sensor GLAS Laser LGS Rotator GLAS BLT Diffractive Optic LGS FSM LGS Dichroic Phase B: Low-order LGS MOAO LGS WFS 1.0’ Diameter LGS asterism
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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 focal plane copy of the full focal plane NGS wfs telescoperotater NGS wfs Adonis DM camera relay optics We have done this at Phase A:
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telescoperotater Adonis DM camera relay optics We planned to do this: NGS wfs NGS wfs dichro LGS wfs
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dichro LGS wfs NGS wfs telescoperotater NGS wfs Adonis DM camera relay optics But ended up designing this so we could fall back to Phase A: This layout is complicated by the crowded focal plane.....
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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
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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
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Altitude range: 11 km to 25 km Asterism range: LGS diagonal on sky between 3.2 m and 3.8 m Change the asterism altitude Change the asterism diameter
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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
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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 Image of 4 LGS asterism taken during testing in 2008 WHT Rayleigh LGS, GLAS, being launched during 2008 CANARY lasers during acceptance testing at Durham (2010)
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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
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AO4ELTs, Paris 2009 CANARY: NGS/LGS MOAO demonstratorDurham Richard Myers, Gordon Talbot, Nigel Dipper, Deli Geng, Eddy Younger, Alastair Basden, Colin Dunlop, Nik Looker, Jonny Taylor, Tim Butterley, Laura Young, Simon Blake, Sofia Dimoudi, Paul Clark Obs. Paris Zoltán Hubert, Gerard Rousset, Eric Gendron, Fabrice Vidal, Damien Gratadour, Aglae Kellerer, Michel Marteaud, Fanny Chemla, Phillipe Laporte, Jean-Michel Huet, Matthieu Brangier UKATC Andy Longmore, David Henry, Stephen Todd, Colin Dickson, Brian Stobie, David Atkinson ONERA Thierry Fusco, Clelia Robert, Nicolas Vedrenne, Jean-Marc Conan ING Jure Skvarc, Juerg Rey, Neil O’Mahoney, Tibor Agocs, Diego Cano PUC Santiago Andres Guesalaga, Dani Guzman L2TI Caroline Kulscar, Gaetano Sevo, Henri-Francois Raynaud Engineering and Project Solutions Ltd Kevin Dee The CANARY project is supported via the following funding bodies STFC STFC UK E-ELT Design Study UK E-ELT Design Study EU FP7 Preparatory fund WP9000 EU FP7 Preparatory fund WP9000 ANR Mauii, INSU, Observatoire de Paris ANR Mauii, INSU, Observatoire de Paris FP7 OPTICON JRA1 FP7 OPTICON JRA1
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