On-sky performance of SPHERE XAO system - Upgrade
Transcription
On-sky performance of SPHERE XAO system - Upgrade
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 • • 3 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 Châtillon, 20-21 janvier 2015 Two major international projects Gemini Planet Imager - GPI Gemini South Amérique du nord PI: Bruce Macintosh Spectro-Polarimetric High-contrast Exoplanet REsearch VLT-UT3 Europe PI: Jean-Luc Beuzit Journées Scientifiques de l’ONERA 4 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 5 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 The global concept of SPHERE SAXO Beam control (DM, TT, PTT, derotation) Pola control Calibration Fore optics High frequency AO correction (41x41 act.) High stability : image / pupil control Visible – NIR Refraction correction FoV = 12.5’’ 40x40 SH-WFS in visible 1.2 KHz, RON < 1e- Vis Coronagraph Extreme AO NIR Coronagraph Common Path Pupil apodisation, Focal masks: Lyot, A4Q, ALC. IR-TT sensor for fine entering Nasmyth platform, static bench, Temperature control, cleanliness control Active vibration control Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Coronagraphic imaging: Dual polarimetry, direct BB + NB. λ = 0.5 – 0.9 µm, λ/2D @ 0.6 µm, FoV = 3.5” ZIMPOL IFS IRDIS 0.95 – 1.35/1.65 µm λ/2D @ 0.95 µm, Spectral resolution: R = 54 / 33 FoV = 1.77” 0.95 – 2.32 µm; λ/2D @ 0.95 µm Differential imaging: 2 wavelengths, R~30, FoV = 12.5’’ Long Slit spectro: R~50 & 400 Differential polarization SPHERE : from the concept … …to reality 7 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 SPHERE : from the concept … …to reality 8 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 SPHERE : from the concept … …to reality 9 Journées Scientifiques de l’ONERA 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 2015 SAXO : 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 11 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 First 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 12 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 First 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 13 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Very first observations Shape structure ρ-3 Diffraction ρ-2 WFS noise ρ0 WFS aliasing Very first image Spatial filter open ρ-3 1 2 ρ-11/3 fitting 3 AO cut-off = 840 mas 4 5 4 / 5 Airy rings clearly visible ρ -2 ρ0 ρ-11/3 WFS spatial filter = open fc= 840 mas 14 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Temporal stability Saturated PSFs 20 min Extremelly good stability of « static » speckle over a complete acquisition sequence 23:19 UT 23:36 UT 15 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Image coronographique – 1ière détection Naine blanche : m = 11 16 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Experience vs simulation 2014/05/16 05:37 UT seeing ~ 0.7 On sky data 1.9 λ/d 1.8 λ/d 1.45 λ/d 1.3 λ/d Simulation 17 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 1.2 λ/d 1.1 λ/d SPHERE vs GPI GPI GP 20 minutes in H band 15 minutes in H2 band HD 165054, G4V, V=8.5 Preliminary reduced data © A. Vigan (LAM) 18 Journées Scientifiques de l’ONERA Châtillon, 20-21 janvier 2015 Summary 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 Tip Tilt modes HODM modes Fitting Grand total variance @ 1.6 µm (rad²) 0.15 0.088 0.04 0.24 Associated SR (%) 86.1 % 91.6 % 96 % 75.1 % SR without TT = 88 % SR with TT = 75 % SR on imgae = 75 % 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 spectrum FAQ : how to win 20% performance ? Shut down M2 !! M2 on M2 off SAXO : monitoring perf and turbulence Strehl r0 Wind DM Sat WFS Flux DTT Position SAXO : 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 data Down 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 Vibration filtering 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 published Perspectives 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 modified