MAORY E-ELT MCAO module project overviewao4elt3.arcetri.astro.it/archive/slides_13380.pdf ·...

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


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


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


MCAO module layout

Pre-focal station

Nasmyth platform

MICADO

Gravity

invariant

port

Lateral

port

Area for detached instrument

MAORY


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)


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


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


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)


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


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


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


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


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


Thank you for your attention

MAORY E-ELT MCAO module project overviewao4elt3.arcetri.astro.it/archive/slides_13380.pdf ·...

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