On-sky performance of SPHERE XAO system Upgrade perspectives - DOTA/HRA J.-F. Sauvage, T. Fusco, C. Petit
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On-sky performance of SPHERE XAO system
-
Upgrade perspectives
J.-F. Sauvage, T. Fusco, C. Petit
DOTA/HRA
Journées Scientifiques de l’ONERA
Châtillon, 20-21 janvier 2015
Science objectives
• High contrast imaging down to planetary masses
• Investigate large target sample: statistics, variety of stellar
classes, evolutionary trends
• Complete the accessible period window
• First order characterization of the atmosphere (clouds,
dust content, Methane, water absorption, effective
temperature, radius, dust polarization)
Understand the planetary system origins
Journées Scientifiques de l’ONERA
Châtillon, 20-21 janvier 2015
Ingredients of a high-contrast imager
• Large telescope
• High performance AO system to compensate for
• Atmospherical turbulence
• Static optical aberrations
• A coronagraphic device to cancel out the main
part of the star light
• Dedicated post-processing methods enhancing
the planet signal wrt the star light residuals
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
Two major international projects
Gemini Planet Imager - GPI Spectro-Polarimetric High-contrast Exoplanet REsearch
Gemini South VLT-UT3
Amérique du nord Europe
PI: Bruce Macintosh PI: Jean-Luc Beuzit
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
SPHERE : An outstanding instrument for VLT
PI : J.-L. Beuzit (IPAG)
PS: D. Mouillet (IPAG)
Ing. Système: K. Dohlen (LAM)
Resp. OA : T. Fusco (ONERA)
12 European institutes
10 years of development
25 M€ (consolidated)
250 FTE
8 tons
6x4x2.5m
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
The global concept of SPHERE
SAXO
Beam control High frequency AO correction (41x41 act.)
(DM, TT, PTT, High stability : image / pupil control Coronagraphic imaging:
derotation) Visible – NIR Refraction correction Dual polarimetry, direct BB + NB.
Pola control FoV = 12.5’’ λ = 0.5 – 0.9 µm,
Calibration 40x40 SH-WFS in visible λ/2D @ 0.6 µm, FoV = 3.5”
1.2 KHz, RON < 1e-
Fore Extreme Vis ZIMPOL 0.95 – 1.35/1.65 µm
optics AO Coronagraph λ/2D @ 0.95 µm,
Spectral resolution: R
IFS = 54 / 33
Common Path NIR
FoV = 1.77”
Coronagraph IRDIS
Pupil apodisation,
Focal masks: Lyot, A4Q, ALC. 0.95 – 2.32 µm; λ/2D @ 0.95 µm
IR-TT sensor for fine entering Differential imaging: 2 wavelengths, R~30,
FoV = 12.5’’
Long Slit spectro: R~50 & 400
Nasmyth platform, static bench, Differential polarization
Temperature control, cleanliness control
Active vibration control
Journées Scientifiques de l’ONERA
Châtillon, 20-21 janvier 2015
SPHERE : from the concept …
…to reality
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
SPHERE : from the concept …
…to reality
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
SPHERE : from the concept …
…to reality
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015
From design to sky : Say what we do, and do what we say
SAXO compliance matrix @ PAE
The on-sky system exactly fits the original design
Glasgow SPIE conf 2004
Journées Scientifiques de l’ONERA
Châtillon, 20-21 janvier 2015SAXO : laboratory performance
Ultimate performance : up to mag 9-10
Still a « decent » correction (a few tens of percent in H) : up to mag 15
2-3 mag better than the specfication !!!!
OCAM² - FLI company
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015First light
4 mai 2014 – 22:28 UT
« May the 4th be with us »
Definition of a First Light:
•First time the star light falls on detector
•Forget to record data
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015First light for SAXO
On sky data (May 2014)
H band 80% SR
J band 70% SR
Y band 60% SR
40x40 EMCCD filtered SH WFS 41x41 Piezzo DM
SAXO, le cœur de SPHERE
un cœur qui bat 1200 fois par seconde
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015Very first observations
Shape structure
Very first image
ρ-3 Diffraction ρ-3 Spatial filter open
1
ρ-2 WFS noise
ρ0 WFS aliasing
2
ρ-11/3 fitting
3
AO cut-off = 840 mas 4
5 ρ -2
4 / 5 Airy rings clearly visible ρ0
WFS spatial filter = open ρ-11/3
fc= 840 mas
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015Temporal stability
Saturated PSFs
20 min
Extremelly good stability of « static » speckle over a complete acquisition sequence
23:19 UT 23:36 UT
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015Image coronographique – 1ière détection
Naine blanche : m = 11
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015Experience vs simulation
2014/05/16
On sky data 05:37 UT
seeing ~ 0.7
1.9 λ/d 1.8 λ/d 1.45 λ/d 1.3 λ/d 1.2 λ/d 1.1 λ/d
Simulation
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015SPHERE vs GPI
GPI
GP
20 minutes in H band 15 minutes in H2 band
Preliminary reduced data
© A. Vigan (LAM)
HD 165054, G4V, V=8.5
Journées Scientifiques de l’ONERA
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Châtillon, 20-21 janvier 2015Summary of SAXO perf (on sky)
Typical seeing / wind speed conditions = medium - bad
SR loss
SR loss
Laboratory data (0.85’’ seeing) x 0.8
Perf evolution vs flux = OK (same as lab)
BUT : SR déficit ~ 15 / 20 %SAXO preliminary on-sky error budget
75 %
Modal variance
Open loop
SR loss = Tip Tilt !!
~ 15 % of SR loss
Close loop
variance @ 1.6 µm (rad²) Associated SR (%)
SR without TT = 88 %
Tip Tilt modes 0.15 86.1 %
HODM modes 0.088 91.6 % SR with TT = 75 %
Fitting 0.04 96 % SR on imgae = 75 %
Grand total 0.24 75.1 %The Tip-Tilt issue
High freq over-excitation ~ 10 mas !!!!
=> SR loss = 15 / 20 %
Open loop TT temporal spectrum
Residual jitter ~ 9 mas rms instead of 2 !
Limitation for very small inner working angle (< 0.1’’)
Limitation for VIS (= Zimpol) images (max SR < 25 %, FWHM > 20 mas)
Problem identified … ESO and SPHERE teams are working on possible solutions
Visible in open loop => not an AO loop issue
Not visible on internal data
Already seen on VLTI data !!!!
Probably related to M2 control
Test to be performed without M2 guiding
Closed loop TT temporal spectrumFAQ : how to win 20% performance ?
Shut down M2 !!
M2 on
M2 offSAXO : monitoring perf and turbulence
Strehl
r0
Wind
DM Sat
WFS Flux
DTT
PositionSAXO : monitoring perf and turbulence
GEN_SPARTA data
Acquired for each OBS template
30s sampling of SAXO quality
Includes DTTS images => Non Corono perf
Now : not completely forwarded in science
archive
Philo : considere RTC as the 4th SPHERE
instrument
Data provided into archive, as well as
science dataDown to very short separations
Imaging in I band (0.8 m) H(0.65 m)
0.15’’
0.34’’
Zimpol PSF
V band (0.55 m) H (0.65 m) I band (0.82 m)SPHERE-SAXO status
COM4
Full features now operational
Vibrationfiltering
Automatic setup with flux
Kalman on TT, OMG…
Full performance validated IR - VIS
15% SR loss explained by secondary mirror
M2 handling compatible with operation
Science Verification
Now over
First papers to be publishedPerspectives
PSF Internal quality can be improved
Simple low order NCPA compensation (LIFT)
Non-linear Dark Hole compensation
(COFFEE)
On-sky estimation of NCPA
Change the deformable mirror
Study pro/cons of different providers
Optics design to be modifiedYou can also read
