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AO4ELT3, Firenze, 27-31 May 2013
MAORY
E-ELT MCAO module
project overview
Emiliano Diolaiti
Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Bologna
On behalf of the MAORY Consortium
2 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
MAORY overview from Phase A
Functions
– Compensate atmospheric turbulence
– Relay telescope focal plane to science instrument
Main requirements related to client instrument MICADO
– Wavelength range 0.8-2.4 µm
– Science field of view 53" 53"
– Uniform adaptive optics correction with high sky coverage
– Gravity invariant exit port
Other requirements
– Lateral exit port for another possible instrument TBC
Expected AO performance
– 50% Strehl Ratio averaged over MICADO field at 2.16 µm wavelength
with 50% sky coverage at the Galactic Pole
– 40% Strehl Ratio with 80% sky coverage at the Galactic Pole
3 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
AO basic choices
Multi-conjugate adaptive optics
– Performance uniformity
– Demonstrated on sky by MAD and GeMS
Laser Guide Stars
– Sky coverage and performance uniformity
– Demonstrated on sky with MCAO by GeMS
Wavefront sensors downstream the deformable mirrors
– Optical feed-back
MAORY DMs WFS Telescope DM
(M4/M5)
SCAO MCAO
MAD Strehl Ratio maps (2.2 µm) © ESO
4 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
MAORY
Client Instrument
E-ELT
Light beam
Signal
(real-time)
Signal
(non real-time)
MCAO module architecture
E-ELT
Common Path Optics
Deformable Mirrors
Dichroic
Science Path Optics LGS Objective
NGS Wavefront Sensor
Exit Port
LGS Wavefront Sensor
Real Time Control System
Telescope Control
System
MAORY
Instrumentation
Software
Client Instrument
Instrumentation
Software
MAORY module
5 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
MCAO module layout
Pre-focal station
Nasmyth platform
MICADO
Gravity
invariant
port
Lateral
port
Area for detached instrument
MAORY
6 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Wavefront Sensors
To M
ICA
DO
Laser Guide Star Wavefront Sensor
– 6 Sodium Laser Guide Stars
– LGS fixed with respect to telescope pupil
– Shack-Hartmann (~80 80 subapertures)
Natural Guide Star Wavefront Sensor
– 3 Natural Stars over 2.6 arcmin field of view
– Limiting magnitude H 21-22
– Each WFS unit is split into two channels:
Tip-Tilt/Focus channel (1.5-1.8µm)
Reference channel (0.6-0.9µm)
7 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Project status
Phase A completed (December 2009)
Project Management Plan for phases B-E in preparation
Consortium consolidation in progress
– INAF: System level responsibility, platform, NGS WFS, deformable
mirrors, auxiliary equipments, science support tools
– Durham University: Real Time Control System
– Observatoire de Paris LESIA: LGS Wavefront Sensor
– ESO: WFS cameras, deformable mirrors, other contributions TBC
8 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Project status
Review of requirements, interfaces and technical choices in collaboration
with ESO
General technology developments within E-ELT project
– Cameras for wavefront sensors
– Deformable mirrors
– Real Time Control System
Specific activities within MAORY project
– Development of end-to-end simulation code optimised for GPU
– Study of wavefront sensing issues
– Design activities
Led by ESO
9 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Wavefront sensing
Spurious low-order aberrations seen by LGS WFS
– Monitored by NGS “Reference” WFS
– Preliminary analysis: residual wavefront error compatible with MAORY
error budget. More detailed analysis required
Detectors for LGS WFS: sampling, field of view
– Phase A: ~1600 1600 pixel detector assumed, i.e. 20 20 pixels/subap.
– Alternative option under analysis: ~800 800 pixel detector
– Trade-off between sampling and field of view in progress
Sodium layer data kindly provided by
Paul Hickson, University of British Columbia
Fie
ld o
f vie
w
Height (km
)
UTC (hrs)
Spurious wavefront map seen by a
LGS WFS due to Sodium layer and
field truncation
(tip, tilt, focus, astigmatism removed)
10 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Wavefront sensor laboratory
prototype
Sodium profile
simulated by LCD
light modulator
Main features
– Multiple sources
– Arbitrary Sodium profile
– Dynamic turbulence (2 layers)
– Low-order deformable mirror
11 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
AO test unit
Some options to test AO performance
– Simulate turbulence by deformable mirrors
– Test with external turbulence simulator
Turbulence simulator design
– Segmented design
– NGS/LGS sources
– Turbulence screens
– M4/M5 emulated by software
NGS sources
LGS sources
NGS focus
LGS focus
Poster by Matteo Lombini
12 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
MAORY post-focal relay
modified baseline optical design
Gravity invariant exit port
Science path
Laser guide star path
Post-focal deformable mirrors
(~400 mm diameter). Baseline piezo-
electric actuator technology. Under
review.
Light beam
from E-ELT
Development activities
– Adaptation to new E-ELT optical
design
– Verification of interfaces to E-ELT
and science instrument
– Feasibility of optical components
– Optimisation of LGS objective
Focus for LGS WFS
13 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Optical schemes for alternative
deformable mirror technologies
Optical designs for “small” ( 150 mm)
deformable mirrors?
Main technical issues
– Longitudinal de-magnification
Intermediate re-imaging is needed between two DMs
Large tilt of layer image with respect to DM surface
– Difficult to obtain diffraction-limited optical performance
Off-axis mirror with
prime focus corrector
Deformable mirror
14 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Optical schemes for alternative
deformable mirror technologies
Optical designs for “large” ( 1100-1200 mm)
deformable mirrors (e.g. voice-coil actuator)?
Main technical issue
– Larger volume than modified baseline design
Gravity invariant
exit port
To LGS objective
LGS objective
15 AO4ELT3, Firenze, 27-31 May 2013 – E-ELT MCAO module project overview
Thank you for your attention