The on-sky NGS/LGS MOAO demonstrator for EAGLE Tim Morris Durham University

The on-sky NGS/LGS MOAO The on-sky NGS/LGS MOAO demonstrator for EAGLEdemonstrator for EAGLE

Tim MorrisTim MorrisDurham UniversityDurham University

AO4ELTs, Paris 2009AO4ELTs, Paris 2009 CANARY: NGS/LGS MOAO demonstratorCANARY: NGS/LGS MOAO demonstrator Tim Morris et alTim Morris et al

Talk overviewTalk overview

MOAO with EAGLEMOAO with EAGLE CANARY conceptCANARY concept Optomechanical designOptomechanical design Subsystem performanceSubsystem performance System performanceSystem performance System calibration tasksSystem calibration tasks


MOAO with EAGLEMOAO with EAGLE

With the current baseline design, EAGLE will:With the current baseline design, EAGLE will: use 6 LGS and up to 5 NGS to map the turbulence above the E-use 6 LGS and up to 5 NGS to map the turbulence above the E-

ELTELT correct up to 20 x ~2” diameter science fields anywhere within correct up to 20 x ~2” diameter science fields anywhere within

the central 5’ diameter field using open-loop AOthe central 5’ diameter field using open-loop AO 250Hz frame rate250Hz frame rate

E-ELT has a deformable ‘secondary’ that will be used as E-ELT has a deformable ‘secondary’ that will be used as a closed-loop woofer (GLAO-like DM)a closed-loop woofer (GLAO-like DM)

EAGLE is both a closed and open-loop systemEAGLE is both a closed and open-loop system

30% ensquared energy with 75mas (H-band) required 30% ensquared energy with 75mas (H-band) required performanceperformance


MOAO with EAGLE: big questionsMOAO with EAGLE: big questions

Can we achieve tomographic reconstruction to the required Can we achieve tomographic reconstruction to the required accuracy over such wide fields? accuracy over such wide fields?

Can we reliably control a DM in open-loop?Can we reliably control a DM in open-loop? How do we calibrate the system?How do we calibrate the system? How accurately do we need to measure the Cn2 profile to optimise performance? How accurately do we need to measure the Cn2 profile to optimise performance? What is the impact of running the system with both open and closed loop DMs?What is the impact of running the system with both open and closed loop DMs? How do we compensate for LGS specific effects that can impact MOAO How do we compensate for LGS specific effects that can impact MOAO

performance?performance? What are the principle performance drivers required when designing an MOAO What are the principle performance drivers required when designing an MOAO

system?system? What is the best way to combine both NGS and LGS WFS signals to measure What is the best way to combine both NGS and LGS WFS signals to measure

tomography?tomography? Answer as many of these questions as possible as soon as possible Answer as many of these questions as possible as soon as possible

to feed into the EAGLE designto feed into the EAGLE design Some can be (and have been) answered in simulation or using a lab Some can be (and have been) answered in simulation or using a lab

system such as SESAMEsystem such as SESAME


CANARY conceptCANARY concept


CANARY AimsCANARY Aims

Perform NGS then LGS based tomographic WFSingPerform NGS then LGS based tomographic WFSing Perform open-loop AO correction on-skyPerform open-loop AO correction on-sky Develop calibration and alignment techniquesDevelop calibration and alignment techniques Fully characterise system and subsystem performanceFully characterise system and subsystem performance

Create a single MOAO channel EAGLE as closely as Create a single MOAO channel EAGLE as closely as possibly using the 4.2m William Herschel Telescopepossibly using the 4.2m William Herschel Telescope

Effectively a 1/10Effectively a 1/10thth scale model of E-ELT using a 10km Rayleigh scale model of E-ELT using a 10km Rayleigh LGSLGS


CANARY phased developmentCANARY phased development

Based around a set of reconfigurable optical Based around a set of reconfigurable optical modules to allow ‘easy’ changes between three modules to allow ‘easy’ changes between three CANARY phasesCANARY phases Phase A: Low-order NGS-only MOAO (2010)Phase A: Low-order NGS-only MOAO (2010) Phase B: Low-order LGS MOAO (2011)Phase B: Low-order LGS MOAO (2011) Phase C: High-order LGS + NGS MOAO (2012)Phase C: High-order LGS + NGS MOAO (2012)

All phases will include an extensive calibration All phases will include an extensive calibration and diagnostics packageand diagnostics package


Diagnostics and Performance monitoringDiagnostics and Performance monitoring On-axis NGS WFS behind AO corrected focal plane On-axis NGS WFS behind AO corrected focal plane

(Truth Sensor)(Truth Sensor) On-axis NIR imaging camera (Science Verification On-axis NIR imaging camera (Science Verification

Camera)Camera) High-order high-bandwidth DM figure sensorHigh-order high-bandwidth DM figure sensor SLODAR analysis performed using open-loop WFSsSLODAR analysis performed using open-loop WFSs External turbulence profilersExternal turbulence profilers

SLODARSLODAR MASS-DIMMMASS-DIMM

Telescope simulatorTelescope simulator Turbulent phase screensTurbulent phase screens NGS and LGS alignment and calibration sourcesNGS and LGS alignment and calibration sources


Phase A : NGS MOAOPhase A : NGS MOAO

Components:Components: Low-order 8x8 DMLow-order 8x8 DM 3 x L3CCD open-loop NGS WFSs3 x L3CCD open-loop NGS WFSs Open-loop optimised Fast Steering Open-loop optimised Fast Steering

MirrorMirror Hardware accelerated Real Time Hardware accelerated Real Time

control systemcontrol system NGS MOAO Calibration UnitNGS MOAO Calibration Unit

WHTNasmyth

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

NGS WFS

NGS WFS

10" Truth sensor& IR camera FOV

2.5’ Derotated WHT field


Phase B: Low-order LGS MOAOPhase B: Low-order LGS MOAO

New modules include:New modules include: Electronically shuttered LGS WFS CCDElectronically shuttered LGS WFS CCD Modified GLAS launch systemModified GLAS launch system LGS dichroic and relay systemLGS dichroic and relay system LGS MOAO Calibration UnitLGS MOAO Calibration Unit

WHTNasmyth

Calibration Unit

NGS Pickoffs

3 x NGS WFS

NGS FSM

Low-order DM


Truth Sensor

LGS Pickoffs

4 x LGS WFS

GHRIL Derotator

Figure Sensor

GLAS Laser

LGS Rotator

GLAS BLT

Diffractive Optic

LGSFSM

LGS Dichroic

Phase B: Low-order LGS MOAO

LGS WFS

1.5’ Diameter LGS asterism


Phase C: High-order LGS MOAOPhase C: High-order LGS MOAO

Closest resemblance to proposed EAGLE MOAO implementationClosest resemblance to proposed EAGLE MOAO implementation Largest upgrade here is to the RTCS. From Phase B we have:Largest upgrade here is to the RTCS. From Phase B we have:

~ 2 times increase in pixel bandwidth~ 2 times increase in pixel bandwidth ~ 5 times increase in slope bandwidth~ 5 times increase in slope bandwidth ~ 17 times increase in actuator bandwidth~ 17 times increase in actuator bandwidth

WHTNasmyth

Calibration Unit

NGS Pickoffs

3 x NGS WFS

NGS FSM

Low-order DM


Truth Sensor

Figure Sensor

LGS Pickoffs

4 x LGS WFS

GHRIL Derotator

MEMS DM

GLAS Laser

LGS Rotator

GLAS BLT

Diffractive Optic

LGSFSM

LGS Dichroic

Phase C: High-order woofer-tweeter LGS MOAO (woofer closed loop)


Optomechanical designOptomechanical design


Phase A optical designPhase A optical design

Input Focal Plane

Output focal plane Truth Sensor focal plane

Science Verification Camera focal plane


Phase B optical designPhase B optical designLGS TT mirror

NGS WFS placed at corrected focal plane

Acquisition camera moved to input focal plane


Phase C optical design conceptPhase C optical design concept

Possible locations of MEMS MOAO DM

LGS WFS(s) moved behind closed-loop DM


NGS WFS AssemblyNGS WFS Assembly


Telescope SimulatorTelescope Simulator


Subsystem performanceSubsystem performance


Open-loop DM ControlOpen-loop DM Control

4% open-loop error with hard PZT DM demonstrated in 4% open-loop error with hard PZT DM demonstrated in laboratory with SESAMElaboratory with SESAME

40nm RMS error if a 1000nm RMS DM surface is requested40nm RMS error if a 1000nm RMS DM surface is requested

Figure sensor could be used to control any long term Figure sensor could be used to control any long term drifts in DM surface shapedrifts in DM surface shape

Will introduce some additional latencyWill introduce some additional latency Has been used with a Xinetics DM and produces a similar Has been used with a Xinetics DM and produces a similar

surface error to the hard PZT DMsurface error to the hard PZT DM

Open loop control of a DM doesn’t seem to be a problem Open loop control of a DM doesn’t seem to be a problem for CANARY low-order DMfor CANARY low-order DM

High-order MEMS DM open-loop control has already been High-order MEMS DM open-loop control has already been demonstrateddemonstrated


Subsystem performance: LGS LaunchSubsystem performance: LGS Launch Test system installed on WHT and tested in MayTest system installed on WHT and tested in May Uses DOE in GLAS launch system to create a 4 star asterism (MMT Uses DOE in GLAS launch system to create a 4 star asterism (MMT

approach)approach) Several possible asterisms available by changing DOESeveral possible asterisms available by changing DOE

10 to 90” diameter asterisms (takes about 15 minutes)10 to 90” diameter asterisms (takes about 15 minutes) 80% of light into 4 diffracted LGS beams but altitude is lowered c.f. GLAS80% of light into 4 diffracted LGS beams but altitude is lowered c.f. GLAS

Still want an upgraded laser to increase WFS SNRStill want an upgraded laser to increase WFS SNR Software problem with LGS detector meant range gated images couldn’t be Software problem with LGS detector meant range gated images couldn’t be

obtainedobtained

Non-gated image of ~40” LGS radius asterism at 6.7km

DOE mounted in rotation stage at GLAS BLT entrance


RTCSRTCS

Hybrid FPGA-CPU Realtime Control SystemHybrid FPGA-CPU Realtime Control System FPGA pixel processing developed for HOT and SPARTAFPGA pixel processing developed for HOT and SPARTA Reconstructor in CPUReconstructor in CPU DM control in CPUDM control in CPU

Currently runs at Phase A/B at 300-400Hz using a single Currently runs at Phase A/B at 300-400Hz using a single threaded reconstructor pipelinethreaded reconstructor pipeline

Latency and jitter to be measuredLatency and jitter to be measured

Upgrade required to cope with high-order LGS WFSs Upgrade required to cope with high-order LGS WFSs and DM in Phase Cand DM in Phase C

Parallelise reconstructorParallelise reconstructor GPU accelerationGPU acceleration


RTCS overviewRTCS overview


System performanceSystem performance


Phase A PerformancePhase A Performance

Monte-Carlo simulations performed using independent codes in Durham Monte-Carlo simulations performed using independent codes in Durham and Paris and Paris

Single open-loop DMSingle open-loop DM 8x8 actuators 8x8 actuators DM (and science path) on-axisDM (and science path) on-axis

3 x NGS WFSs3 x NGS WFSs Off-axis (30” to 90”)Off-axis (30” to 90”) 7 x 7 subapertures7 x 7 subapertures 0.1e- read noise0.1e- read noise Mv = 8 to 14Mv = 8 to 14 250Hz frame rate250Hz frame rate

Representative summer La Palma turbulence profile usedRepresentative summer La Palma turbulence profile used1

rr00 = 12cm = 12cm 45% @ 0km45% @ 0km 15% @ 2.5km15% @ 2.5km 30% @ 4km30% @ 4km 10% @ 13.5km10% @ 13.5km

1 Fuensalida et al, RevMexAA, 31, 84-90 (2007)


Simulated PerformanceSimulated PerformanceSource of errorSource of error WFE (nm rms)WFE (nm rms)

WFS open-loop estimationWFS open-loop estimation 63 (from YAO)63 (from YAO)

WFS noise (quantum + readout)WFS noise (quantum + readout) 40 at m40 at mRR=10=10

80 at m80 at mRR=12=12

190 at m190 at mRR=14=14

Tomographic reconstruction (30’’ radius)Tomographic reconstruction (30’’ radius) 260 (GLAO least-square)260 (GLAO least-square)220 (tomographic least square)220 (tomographic least square)170 (L&A MMSE) (Vidal et al)170 (L&A MMSE) (Vidal et al)

DM fittingDM fitting 140140

DM open-loop errorDM open-loop error 4848

Tip-tilt open-loop errorTip-tilt open-loop error 2626

Temporal and aliasingTemporal and aliasing 113113

Residual high-orders from opticsResidual high-orders from optics 5050

TOTALTOTAL mmRR=12 : 285 to 340=12 : 285 to 340


Error termsError terms Principle term is tomographic reconstruction Principle term is tomographic reconstruction

errorerror 30” radius means metapupils at highest turbulent 30” radius means metapupils at highest turbulent

layer are almost completely separatedlayer are almost completely separated 30” is still pretty small to find a 4-star mv = 12 30” is still pretty small to find a 4-star mv = 12

asterismasterism Have identified several suitable targets within a Have identified several suitable targets within a

2.5’ diameter FOV observable between June-2.5’ diameter FOV observable between June-October October

Will be even worse with the 10km Rayleigh LGS Will be even worse with the 10km Rayleigh LGS at Phases B and Cat Phases B and C

Requires the external turbulence profiling to Requires the external turbulence profiling to determine how much of the turbulence is above determine how much of the turbulence is above the LGSthe LGS

The Truth Sensor will be used as the principle The Truth Sensor will be used as the principle system diagnosticsystem diagnostic

Science camera can be used when the Science camera can be used when the turbulence cooperatesturbulence cooperates

>60% turbulence in the ground layer is often >60% turbulence in the ground layer is often observed at the WHTobserved at the WHT


System CalibrationSystem Calibration


Phase A calibrationPhase A calibration Interaction matrix measurement using a Interaction matrix measurement using a

reverse path calibration sourcereverse path calibration source On-axis point source pointing backwards at On-axis point source pointing backwards at

output focal plane can be observed by each output focal plane can be observed by each NGS WFS in turnNGS WFS in turn

Requires stable pupil image at lenslet array Requires stable pupil image at lenslet array across full FOVacross full FOV

Or use TS to measure DM influence functions Or use TS to measure DM influence functions Observe ground-layer only turbulent sources Observe ground-layer only turbulent sources

within the telescope simulator with NGS WFSs within the telescope simulator with NGS WFSs and TSand TS

Translate TS measure influence functions to Translate TS measure influence functions to each DMeach DM

Or measure matrices on-skyOr measure matrices on-sky Learn and Apply method from Fabrice Vidal first Learn and Apply method from Fabrice Vidal first

thing this morningthing this morning

From telescope

From reverse path calibration source

ToWFS

NGS WFS pickoff prism


Other calibration tasksOther calibration tasks

Field dependent aberrationsField dependent aberrations Pupil image stability is <1/100Pupil image stability is <1/100 thth pupil diameter pupil diameter Monitoring and compensation changing field aberrationsMonitoring and compensation changing field aberrations

Non-common path error compensationNon-common path error compensation Deployable point sources in most focal planesDeployable point sources in most focal planes Some pointing backwards for reverse path calibrationSome pointing backwards for reverse path calibration

WFS linearity/gain optimisation (for WCOG etc.)WFS linearity/gain optimisation (for WCOG etc.) Use sources in NGS focal planeUse sources in NGS focal plane

NGS pickoff positioning accuracyNGS pickoff positioning accuracy Confirm with full field acquisition cameraConfirm with full field acquisition camera

Detector calibrationDetector calibration At Phase B/C:At Phase B/C:

LGS WFS offsets/centroid gainLGS WFS offsets/centroid gain Range gate setting and optimisation Range gate setting and optimisation LGS WFS interaction matrixLGS WFS interaction matrix

To be developed further during the Integration and Testing phaseTo be developed further during the Integration and Testing phase Runs from October 09 – April 10Runs from October 09 – April 10


ConclusionsConclusions

Already answered some of the big questions that MOAO Already answered some of the big questions that MOAO with EAGLE raiseswith EAGLE raises

Open-loop DM controlOpen-loop DM control Several calibration schemes proposedSeveral calibration schemes proposed

CANARY will have the capability to answer the CANARY will have the capability to answer the remaining ones by demonstrating and testing wide-field remaining ones by demonstrating and testing wide-field LGS tomographic AOLGS tomographic AO

Critical subsystems are being testing and the initial Critical subsystems are being testing and the initial integration phase is about to beginintegration phase is about to begin

We’re on track to go on-sky mid 2010 with the Phase A We’re on track to go on-sky mid 2010 with the Phase A NGS tomography experimentNGS tomography experiment

Phase B design to be reviewed at the end of this yearPhase B design to be reviewed at the end of this year


The CANARY teamThe CANARY teamDurhamDurham Richard Myers, Gordon Talbot, Nigel Dipper, Deli Geng, Eddy Richard Myers, Gordon Talbot, Nigel Dipper, Deli Geng, Eddy

Younger, Alastair Basden, Colin Dunlop, Nik Looker, Jonny Younger, Alastair Basden, Colin Dunlop, Nik Looker, Jonny Taylor, Mark Harrison, Tim Butterley, Dani Guzman, Laura Taylor, Mark Harrison, Tim Butterley, Dani Guzman, Laura Young, Simon Blake, Sofia DimoudiYoung, Simon Blake, Sofia Dimoudi

Obs. ParisObs. Paris Zoltán Hubert, Gerard Rousset, Eric Gendron, Fabrice Vidal, Zoltán Hubert, Gerard Rousset, Eric Gendron, Fabrice Vidal, Damien Gratadour, Aglae Kellerer, Michel Marteaud, Fanny Damien Gratadour, Aglae Kellerer, Michel Marteaud, Fanny Chemla, Phillipe LaporteChemla, Phillipe Laporte

UKATCUKATC Andy Longmore, David Henry, Stephen Todd, Colin Dickson, Andy Longmore, David Henry, Stephen Todd, Colin Dickson, Brian StobieBrian Stobie

ONERAONERA Thierry Fusco, Clelia Robert, Nicolas VedrenneThierry Fusco, Clelia Robert, Nicolas Vedrenne

INGING Jure SkvarcJure Skvarc

PUC SantiagoPUC Santiago Andres GuesalagaAndres Guesalaga

Herriott-WattHerriott-Watt Alan Greenaway, Heather DalgarnoAlan Greenaway, Heather Dalgarno

Engineering and Engineering and Project Solutions LtdProject Solutions Ltd

Kevin DeeKevin Dee


CANARY capabilitiesCANARY capabilities

CANARY can:CANARY can: Perform, calibrate and characterise accuracy of open-loop LGS Perform, calibrate and characterise accuracy of open-loop LGS

tomography on-skytomography on-sky Measure/monitor everything to make sure we understand performance Measure/monitor everything to make sure we understand performance

of each component as well as the system as a wholeof each component as well as the system as a whole Develop alignment and calibration techniquesDevelop alignment and calibration techniques Combine several off-axis NGS and LGS WFSs to map the turbulence Combine several off-axis NGS and LGS WFSs to map the turbulence Eventually use a closed-loop woofer and open-loop tweeterEventually use a closed-loop woofer and open-loop tweeter Emulate arbitrary LGS intensity profiles and elongationEmulate arbitrary LGS intensity profiles and elongation

CANARY cannot:CANARY cannot: Reach EAGLE performance goalReach EAGLE performance goal Match the total number of subapertures/actuators within EAGLEMatch the total number of subapertures/actuators within EAGLE Match the exactly LGS/NGS FOV afforded by the E-ELTMatch the exactly LGS/NGS FOV afforded by the E-ELT Take advantage of the multiplex normally afforded by MOAO – only a Take advantage of the multiplex normally afforded by MOAO – only a

single channel single channel

Documents

The on-sky NGS/LGS MOAO demonstrator for EAGLE Tim Morris Durham University