Presentation on theme: "Thierry Fusco Gérard Rousset NAOS-CONICA (a.k.a NACO) for the VLT."— Presentation transcript:
Thierry Fusco Gérard Rousset NAOS-CONICA (a.k.a NACO) for the VLT
ESO, 27/11/ NACO History ~5 years CFT for the VLT Coude AO feasibility study: Feb. 91 CONICA contract signed with MPIA et al: 1991 VLT Coude AO feasibility study: Matra-Marconi-Space in VLT Coude AO project (4 AO systems) cancelled: Council Dec 93 NAOS concept is proposed by ESO to STC-FC-Council: end 1994 CONICA is redesigned by MPIA et al.: end 1994 NAOS Preliminary Inquiry & CFT: Dec. 94- March 96 NAOS audit: March 96- December 96 NAOS contract signed with ONERA et al.: March 97 CONICA FDR: mid 98 NAOS PDR - FDR: Oct June 99 NAOS-CONICA PAE: Sept NAOS-CONICA first light: Nov NACO open to the community: Oct 2002
ESO, 27/11/ NAOS in figures 4 Institutes : ONERA, LAOG, ODP, ESO §5-year project §~5 Meuros §60 FTEs §Tests in France in 2001 §First light 25/11/2001 §NAOS: 2.3 tons CONICA: 0.9 tons (attached to Nasmyth rotator)
ESO, 27/11/ Two Shack-Hartmann Wavefront Sensors, each including 2 pupil samplings: 14x14 (144 valid subap.) and 7x7 (36) NAOS main features (1/2)… IR WFS : Spectral range: mm 14x14 array + 2 arrays of 7x7 on 3 fixed detector areas (0.8 and 0.4 arcsec/pix) Rockwell Hawaii 1024x1024 pixels frame rate from 180 to 15 Hz noise : from 10 to 20 e- 36 configurations !!! VWFS : Spectral range: mm 2 interchangeable lenslet arrays (0.29 and 0.58 arcsec/pixel) EEV CCD 128x128 pixels, 16 outputs (ESO) frame rate from 444 to 15 Hz binning, windowing noise : 2.9e- to 5.4e- 48 configurations!!!
ESO, 27/11/ NAOS main features (2/2) Dichroic Wheel: 2 neutral and 3 dichroic BS WFS Field Selector: NGS in 2 arcmin FOV Tracking (refraction, flexures, moving object) Deformable mirror (Cilas) 185 actuators (piezo-stacked), 10 m stroke 2-axis Tip/Tilt Mirror: 2.1 mas resolution Real time Computer (Shakti): 0dB Error BW: 27 Hz (V) and 22 Hz (IR) modal optimization (every 2 mn) on-line performance and seeing Off-line preparation software Observation software: NAOS configuration, control of Field Selector Aberration pre-compensation, chopping
ESO, 27/11/ Flange to rotate CONICA Imaging: 1-5 µm Polarisation Coronography Spectro 1-5 µm: max 2500 Fabry Perot: R=1800
ESO, 27/11/ VLT Nasmyth Platform NAOS CONICA VLT-UT4: F/15 Cable twist … and NAOS-CONICA became NACO … They lived happy everafter … and they had plenty of photons …
ESO, 27/11/ High order correction in near IR (Sr(K)=70%) Faint limiting magnitude star in V (Mv>17) IR wavefront sensing for embedded objects Compatibility with LGS operation Minimization of instrument thermal and sky bkg effects Minimise the number of optical surfaces no derotator direct rotation of NACO AO with Chopping and Counter chopping Very low flexure requirements (NAOS & CONICA) background limiter to reduce dichroic background High image quality for CONICA (Sr(K)>90%) Low Instrumental background <1e One detector for 1-5 m! Many CONICA observing modes: Imaging, coronagraphy, Low resolution spectroscopy, FP, polarimetry And now … lets go on sky … with a pit-stop in lab NACO challenges
ESO, 27/11/ Result: SR arcsec seeing (specification 70 %) First laboratory results Turbulent imageAO corrected imageImage without turbulence SR = 69% 90% Seeing 0.6 arcsec
ESO, 27/11/ Paranal re-integration NOOOOOOOO ! Oh my god … I have to make it work ! YESSSSSSSS ! Im gonna observe in J, H, K, L, M … Im gonna detect exoplanets The astronomer The instrumentalist (use to be an astronomer )
ESO, 27/11/ Lets go on the telescope Is this going to work?? Well … maybe... Of course it will !!!!!!!!!!
ESO, 27/11/ High Strehl ( K ) 50% And yes … it worked and it is still working
ESO, 27/11/ Faint star correction Strehl (K)=17%
ESO, 27/11/ The Galactic Centre with and without AO in L'-band seen by NAOS (Clénet et al. 2004) The Galactic Centre
ESO, 27/11/ Thetis Differential tracking Composite image H-K 20.6 arcsec diameter resolution 70 mas or 410 km ~10 sec exposure time
ESO, 27/11/ Io with NAOS-CONICA Long wavelengths capabilities Br -L 230/4.2 s exposure 68mas or 210 km 1.2 arcsec diameter
ESO, 27/11/ On-sky SR behavior versus magnitude Visible WFS IR WFS Bright NGS : SR loss of % Faint NGS : significant correction Stars: seeing 0.7, crosses: 1.1, diamonds: 1.1 ; 14x14 arrays: large symbols, 7x7 arrays: small symbols
ESO, 27/11/ Exoplanet detection with NACO
ESO, 27/11/ SR loss sources (1/2) Vibrations detected on WFS data: On-sky Laboratory No vibration Vibration lines Hz : nm² Hz : nm² Hz : nm² No vibration on Comas Variations in amplitude and occurence No vibration in laboratory Nothing on internal source: telescope vibrations
ESO, 27/11/ SR loss sources (2/2) Telescope vibrations: Strehl loss estimated to 10 % Main influence on Tip-Tilt modes but other excitations detected on high order modes Vibrations not compensated for: out of the NAOS temporal bandwidth
ESO, 27/11/ Differential aberrations in CONICA and dichroics Without turbulence, SR ~ 93 % in K with pre-compensation With pre-compensation by NAOS deformable mirror No compensation At 2.15 m At 1.09 m SR = 93 %SR = 89 % SR= 56%SR =66%
ESO, 27/11/ Conclusion §In median seeing conditions: SR ~ 50% at K band; best Sr(K)=64% on sky §Substantial compensation with very faint NGS: Mv=17.6, SR=6% (gain of 7) §Fully automated operation (VLT software) §Many features available in NAOS for specific astronomical observations: l IR WFS l differential refraction, pointing model l tracking on moving object, l chopping, counter-chopping §241 scientific papers so far => 34.5 papers per year => Good scientific return !