MULTIPLE OBJECT
ADAPTIVE OPTICS
Mixed NGS/LGS Tomography
Tim Morris (Durham University, UK)
and
Eric Gendron, Alastair Basden, Olivier Martin, David Henry, Zoltan Hubert, Gaetano Sivo, Damien
Gratadour, Fanny Chemla, Arnaud Sevin, Matthieu Cohen, Eddy Younger, Fabrice Vidal, James
Osborn, Richard Wilson, Tim Butterley, Urban Bitenc, Dani Guzman, Javier de Cos Juez, Andrew
Reeves, Nazim Bharmal, Henri-Francois Raynaud, Caroline Kulcsar, Jean-Marc Conan, JeanMichel Huet, Denis Perret, Colin Dickson, David Atkinson, Tom Baillie, Andy Longmore, Stephen
Todd, David Anderson, Colin Bradley, Olivier Lardiere, Gordon Talbot, Simon Morris, Richard
Myers and Gerard Rousset
Overview
• MOAO instrumentation
• CANARY Status
• CANARY Results
• SCAO, GLAO, MOAO, LTAO
• Bench and on-sky
• CANARY development
MOAO instrumentation
• First on-sky open-loop AO systems used on-axis guide
star to control a single on-axis DM
• ViLLaGeS1 and VOLT2 demonstrated open-loop AO on-sky in 2007
& 2008 respectively
• Proved that open-loop control of AO systems was feasible
• Laboratory test benches were developed that were
capable of investigating wavefront tomography and
control
• UCO/LAO tomographic AO testbench3 at UCSC
• SESAME at the Observatoire de Paris
• Combining open-loop control with wavefront tomography
gave rise to instrument concepts such as FALCON and
EAGLE
1.
2.
Gavel et al, Proc. SPIE Vol. 6888, p688804 (2008)
Andersen et al, Proc. SPIE Vol. 7015, p70150H (2008)
3.
Ammons et al, Proc. SPIE Vol. 6272, p627202 (2006)
RAVEN
• RAVEN is a 2-channel
MOAO system being built
for the Subaru telescope.
• Feeds existing slit-based
spectrograph
• Uses 3 off-axis NGS
within a 3.5’ FOV
• 15th magnitude NGS goal
• Can also use Subaru’s on-
axis sodium LGS
• First light planned for May
2014
RAVEN
• Currently assembled in the UVic
AO lab and undergoing initial
laboratory AO testing
• SCAO > MOAO > GLAO
• For more information see posters
by:
• Olivier Lardière (RAVEN status)
• Kate Jackson (RAVEN tomography)
No AO
Open-loop GLAO
0.7
0.6
0.6
0.6
0.6
0.5
0.5
0.5
0.4
0.3
arcsec.
IRCS slit
0.4
0.3
arcsec.
0.7
arcsec.
0.7
0.5
arcsec.
Closed-loop AO
MOAO
0.7
0.4
0.3
0.4
0.3
0.2
0.2
0.2
0.2
0.1
0.1
0.1
0.1
0
0
0
0.2
0.4
arcsec.
0.6
0
0
0.2
0.4
arcsec.
0.6
0
0.2
0.4
arcsec.
0.6
0
0
0.2
0.4
arcsec.
0.6
Science camera images (l=1.0-1.7mm) after 1s of turbulence history. NGS asterism radius = 40 arcsec.
CANARY
• An open-loop tomographic AO demonstrator on the 4.2m William
Herschel Telescope in La Palma
• Split into 3 phases of increasing complexity
• Phase A: NGS-only open-loop tomographic AO (2008-2010)
• Phase B: Mixed NGS and LGS open-loop tomographic AO (2010-2013)
• B1: Single LGS
• B2: Multiple LGS
• Phase C: Mixed NGS and LGS open-loop tomographic AO with a closed-loop
GLAO/LTAO DM (2014+)
3’ DEROTATED TECHNICAL FIELD OF VIEW
3 OFF-AXIS OPEN-LOOP NGS UP TO MV ~ 11-12
ON-AXIS CORRECTED SCIENCE/VERIFICATION PATH
CANARY so far...
• Phase A (NGS only) completed 2010
• Seeing-limited (NoAO) (SR=1%)
• GLAO (SR=9%)
• MOAO (SR=19.4%)
• SCAO (SR=23.8%)
Asterism 47 and Phase A AO
performance at 1.53μm
• Phase B1 (3 NGS + 1 LGS) commissioned June 2012
• Almost identical to RAVEN configuration (except on a 4m telescope with a
Rayleigh LGS)
• Phase B2 (3 NGS + 4 LGS) first on-sky commissioning run
finished yesterday morning
CANARY Phase B1
• Single LGS that could be positioned anywhere within a ~1’ FOV
• In practice, LGS remained on-axis
• LGS altitude was fixed at 13.5km
• Provided photon return ‘safety margin’
13.5km distant LGS WFS image
750m range gate
~4” per subaperture
CANARY Phase B2: 4LGS WFS
ACQUISITION
• 3 nights on-sky with the
Phase B2 system from 23rd to
25th May
CAMERA
PYRAMID
• 6 nights scheduled in July
• New for Phase B2: 4LGS
FIELD STOP
LGS WFS
WFS
• 128 x 128 pixel camera from
MIT-LL/Scimeasure
• >1000:1 contrast ratio integrated
shutter
• Pyramid-based asterism
selection
• 21km central LGS focal
distance
• 23” radius asterism
• 1.5km range gate depth
• 1.2” elongation
LENSLET
Rayleigh Fratricide
• Laser outputs more light at pulse rates > 10kHz
• Minimum laser pulse rate defines maximum altitude
• 10kHz allows a maximum LGS focal distance of 15000m
• Optical system defines what altitudes can be observed
CANARY Phase B2: Profiling
• New Stereo-SCIDAR turbulence profiler in addition to
SLODAR and CANARY WFSs
• See talk by James Osborn on Wednesday 15:20
SLODAR @ Pt5M
SCIDAR @ JKT
CANARY @ WHT
Profiling
Altitude (m)
• Stereo-SCIDAR
• CANARY Open-loop • SLODAR
• High vertical
WFSs
• Up to ~6km using existing
resolution
binary targets
• Up to 4 NGS and LGS
• ~200m (at altitudes
for multi-baseline
• Total turbulence strength
>0km)
SLODAR profiling
• Wind velocities
• Monitoring
• Takes telescope time
Relative turbulence strength (%)
CANARY results
• Comprehensive analysis
of Phase A/B results will
be presented in this
afternoon’s talk by Olivier
Martin (@ 1700)
• Results of the LQG onsky reconstructor are
going to be presented by
Gaetano Sivo on Friday
• Here we present initial
results from the Phase B2
run
CANARY Phase B2 system at the WHT Nasmyth
platform
NGS & LGS MOAO
• Three star test asterism (Ast T1)
• RA: 13 41 38.2, Dec: +07 36 21
• Mb= 10.4, 11, 11.1
• 3-layer tomographic reconstructor fitted
GLAO
SCAO
NGS + LGS MOAO
Altitude (m)
• NIR PSFs recorded at 1530nm
Relative turbulence strength (%)
SR = 9.9%
SR = 21.5%
SR = 15.2%
NGS & LGS MOAO
Results from single dataset taken switching between SCAO,
combined NGS & LGS tomography and combined NGS & LGS
GLAO
Strehl Ratio at 1.53μm
SCAO
MOAO
(4 LGS + 2
NGS)
GLAO
(4 LGS + 2
NGS)
Hour (UT)
NGS & LGS MOAO
• A few caveats:
Strehl Ratio at 1.53μm
• CANARY is a low-order 7x7 system
• High frequency errors in the DM surface
leave us with a large residual static error
• A few obvious points:
• SCAO > MOAO > GLAO
• GLAO still pretty good!
Atmospheric r0 (m)
• A few less obvious points:
• CANARY data has shown WHT
performance dominated by GL
turbulence
• Quasi-static error term affecting
MOAO results
• This term is difficult to calibrate and is
partially due to varying field
aberrations caused by the derotator
Asterism 32
Open-loop LTAO
• CANARY LGS asterism diameter has been
selected to optimise on-axis performance
• Optimal performance is found when LGS are
positioned at ~ 1 pupil diameter at altitude
• No fundamental difference between CANARY 4
LGS MOAO configuration and optimal LTAO
configuration
• Open-loop operation vs. Pseudo open-loop
SCAO
LTAO
SR = 21.6%
SR = 14.7%
2 Tip-Tilt, 4 LGS
On-sky tomography testing
• Have on-sky data for a wide variety of tomographic
configurations:
• SCAO
• Mixed NGS and LGS MOAO
• 0 & 4 LGS, 1-3 NGS stars
• LGS-only MOAO (Open-loop LTAO)
• 4 LGS, 1-3 TT stars
• Mixed NGS and LGS GLAO (open-loop)
• 4 LGS, 1-3 NGS stars
• LGS only GLAO (open-loop)
• 4 LGS, 1-3 TT stars
• Have taken corrected datasets for both minimum variance and
LQG reconstructors for most of these
• Bench validation using the CANARY telescope simulator is the
first step
Bench tomography testing
• Turbulence generated using
telescope simulator,
initial
fitted
• 2 layers at 0 and 5200m
• 70% at ground, 30% alt.
• r0 = 11 cm, L0≈12 m
• Windspeed ≈ 6m/s
• NGS configured to simulate
CANARY asterism A47
NGS1
NGS2
NGS3
-43.4
47.3
28.3
20.4
21.4
-28.8
• Square LGS asterism
• 21.6’’ off-axis
• Altitude 17000m
40
20
0
−20
−40
−60
−40
−20
0
20
40
4LGS+2NGS
0.30
4LGS+3TT
4LGS+2TT
SCAO
0.25 4LGS+3NGS
at 1.55μm
Strehl Ratio
srir
3LGS + 3NGS
0.20
3NGS
0.15
4LGS+1NGS
0.10
4LGS+1TT
1LGS+3NGS
GLAO 4LGS+3NGS
2LGS+3NGS
0.05
0.00
−2.7
−2.6
−2.5
Hour (UT)
−2.4
−2.3
CANARY: A Flexible Testbench
• CANARY doesn’t only demonstrate MOAO!
• Reconfigurable optical layout allows many other tests
• New WFSs
• LGS WFSing with controlled elongation
• Linux-based RTCS has been readily adapted as the project has
progressed
• Many new centroiding techniques
• New reconstructors
• Several talks/presentations this week about techniques developed and
tested/to-be tested on-sky using CANARY
Topic
Who
What
When
On-sky phase diversity
Damien Gratadour
Talk
Today 17:40
Open-loop tomography
Olivier Martin
Talk
Today 17:00
LQG reconstruction
Gaetano Sivo
Talk
Friday 12:00
Real-time Control Systems
Richard Myers
Talk
Friday 14:20
On-sky CuRe-type reconstructors tests
Urban Bitenc
Poster
Sodium LGS elongation studies
Gerard Rousset
Poster
Tomography with Artificial Neural Networks
• Using machine learning to generate a robust tomographic
reconstructor
• Advantages:
• Includes non-linear effects difficult to model
• Single reconstructor optimal for all turbulence profiles
• Disadvantages:
• Requires a large amount of training data
• Training process can take a long time for large systems
• For CANARY: L&A: 1minute, ANN: 10 minutes
• Valid only for a given asterism
• Good for LGS systems!
ANN Tomography
• Trained an ANN reconstructor using
CANARY bench measurements
• Compared to L&A reconstructor trained on a
2-layer atmosphere (0km and 2.8km)
• Reconstructed on-axis WFS slopes whilst
changing conjugate altitude of high layer
WFS x 3
CANARY future
• Phase C1: LTAO (on-sky
May/July 2014)
• Design review next week
• Reorganisation of the bench to
place WFSs behind DM
• Additional figure sensor for
pseudo open-loop operation
Y
X
Z
3D Layout
• Phase C2: E-ELT
TRUTH
11/04/2013
configuration MOAO (on-sky
2015)
• Closed-loop GLAO DM
(existing low-order DM)
• Open-loop MOAO DM (highorder DM)
• High order figure sensor
• High order LGS WFSs
phase C end-to-end optical design MCAO
Configuration
Photon return
• Defines optimal LTAO error at
Phase C1
• Defines how many subapertures
we can use at Phase C2
• LGS photon return
measured at Phase B1
on a single LGS
• Varying RGD makes this
easy!
• Projected to 4 LGS
Phase C1/2
Beyond Phase C
• Funding has been secured for further on-sky
investigations with CANARY:
• Focal plane NIR WFSing
• E-ELT scale LGS elongation WFS study
• Several ideas have been proposed for later phases:
• Open-loop MCAO demonstration
• LGS uplink tomography for tip-tilt determination
• Additional technology demonstrations planned:
• On-sky demonstration of AO-coupled integrated photonic
spectrograph
• Always open to new collaborations that will benefit from
an on-sky test…
Conclusions
• CANARY is now almost in its final configuration with a
world record (?) 8 full frame rate, high-order wavefront
sensors
• We have demonstrated mixed NGS and LGS open-loop
tomography on-sky
• Additional results this afternoon!
• LGS MOAO works and can provide much better
performance than LGS GLAO
• Closed-loop LTAO and high-order MOAO on-sky in
2014/15 repsectively
System Growth
• CANARY complexity has increased since
initial testing phase in early 2009
• Currently have 8 WFS’s , 25 reference
sources and 288 WFS subapertures
Number of WFSs
Number of reference
sources
Number of WFS
subapertures

Durham
Richard Myers, Gordon Talbot, Nigel Dipper, Deli Geng, Eddy Younger, Alastair Basden,
Colin Dunlop, Nik Looker, Tim Butterley, Laura Young, Simon Blake, Sofia Dimoudi, Paul
Clark, Nazim Bharmal, Richard Wilson, Harry Shepherd, James Osborn, Urban Bitenc,
Andrew Reeves, Simon Morris
Observatoire
de Paris
Zoltán Hubert, Gerard Rousset, Eric Gendron, Fabrice Vidal, Damien Gratadour, Aglae
Kellerer, Michel Marteaud, Fanny Chemla, Phillipe Laporte, Jean-Michel Huet, Matthieu
Brangier, Olivier Martin, Mathieu Cohen, Denis Perret, Arnaud Sevin,
UKATC
David Henry, Stephen Todd, Colin Dickson, Brian Stobie, David Atkinson, Tom Bailie,
Martin Black, Andy Longmore
ONERA
Jean-Marc Conan, Thierry Fusco, Clelia Robert, Nicolas Vedrenne
ING
Jure Skvarc, Juerg Rey, Neil O’Mahoney, Tibor Agocs, Diego Cano, Don Carlos Abrams
IOGS
Caroline Kulscar, Henri-Francois Raynaud, Gaetano Sivo
Others
Andres Guesalaga (PUC Santiago), Dani Guzman (PUC Santiago), Javier de Cos Juez
(University of Ovideo)
The CANARY project is supported via the following funding bodies




STFC, UK E-ELT Design Study
EU FP7 Preparatory fund WP9000
ANR Maui, INSU, Observatoire de Paris
FP7 OPTICON JRA1
AO4ELTs, Paris 2009
CANARY: NGS/LGS MOAO DEMONSTRATOR