1. NAOS-CONICA (a.k.a NACO) for the VLT
3/25/2017
NAOS-CONICA (a.k.a NACO) for the VLT
Thierry Fusco
Gérard Rousset

2. NACO History
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 92-93
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. 2001
NAOS-CONICA first light: Nov. 2001
NACO open to the community: Oct 2002
~5 years

3. NAOS in figures 4 Institutes : ONERA, LAOG, ODP, ESO 5-year project
3/25/2017
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) 3

4. NAOS main features (1/2)…
3/25/2017
Two Shack-Hartmann Wavefront Sensors,
each including 2 pupil samplings:
14x14 (144 valid subap.) and 7x7 (36)
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!!!
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 !!! 4

5. NAOS main features (2/2) Deformable mirror (Cilas)
3/25/2017
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
Dichroic Wheel:
2 neutral and 3 dichroic BS
WFS Field Selector:
NGS in 2 arcmin FOV
Tracking (refraction, flexures, moving object)
Observation software:
NAOS configuration, control of Field Selector
Aberration pre-compensation, chopping
Off-line preparation software 5

6. Mechanical structure Diameter: 2m Max Length: 3m Thickness: 0.7m PM 2
V-WFS
IR WFS
Diameter: 2m
Max Length: 3m
Thickness: 0.7m
TTM DM
Output
input
PM 1

7. Pupil sampling Telescope pupil 144 useful subapertures
185 useful actuators
144 useful subapertures
Central obscuration

8. CONICA 1-5 microns (1Kx1K) 34 filters 4 grisms 7 cameras 3 slits
3/25/2017
CONICA
1-5 microns (1Kx1K)
34 filters
4 grisms
7 cameras
3 slits
Polarimetry
Coronography
Fabry-Perot Imaging 8

9. Flange to “rotate” CONICA
Imaging: 1-5 µm
Polarisation
Coronography
Spectro 1-5 µm: max 2500
Fabry Perot: R=1800

10. They lived happy everafter … and they had plenty of photons …
… and NAOS-CONICA became NACO …
They lived happy everafter … and they had plenty of photons …
NAOS
CONICA
Cable twist
VLT-UT4: F/15
VLT Nasmyth Platform

11. NACO challenges And now … let’s go on sky … with a pit-stop in lab 
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 … let’s go on sky … with a pit-stop in lab 

12. First laboratory results
3/25/2017
First laboratory results
Turbulent image
AO corrected image
Image without
turbulence
Seeing 0.6 arcsec
SR = 69%
90%
Result: SR 65 % @ 0.93 arcsec seeing (specification 70 %) 12

13. Paranal re-integration
NOOOOOOOO !
Oh my god …
I have to make it work !
YESSSSSSSS ! I’m gonna observe in
J, H, K, L, M …
I’m gonna detect exoplanets
The instrumentalist
(use to be an astronomer )
The astronomer

14. Let’s go on the telescope
Is this going to work??
Well … maybe ...
Of course it will !!!!!!!!!!

15. And yes … it worked and it is still working
High Strehl (K)
50%

16. Faint star correction
Strehl (K)=17%

17. The Galactic Centre with and without AO in L'-band seen by NAOS
3/25/2017
The Galactic Centre
The Galactic Centre with and without AO in L'-band seen by NAOS
(Clénet et al. 2004)

18. Thetis
Composite image H-K
20.6 arcsec diameter
resolution 70 mas or 410 km
~10 sec exposure time
Differential tracking

19. Long wavelengths capabilities
Io with NAOS-CONICA
Long wavelengths capabilities
Brg-L’
230/4.2 s exposure
68mas or 210 km
1.2 arcsec diameter

20. On-sky SR behavior versus magnitude
3/25/2017
On-sky SR behavior versus magnitude
Visible WFS
IR WFS
Stars: seeing £ 0.7 ’ ’, crosses: £ 1.1 ’ ’, diamonds: > 1.1 ’ ’ ;
14x14 arrays: large symbols, 7x7 arrays: small symbols
Bright NGS : SR loss of %
Faint NGS : significant correction 20

21. Exoplanet detection with NACO

22. SR loss sources (1/2) No vibration in laboratory
Vibrations detected on WFS data:
On-sky
Laboratory
No vibration
Hz : nm²
Hz : nm²
Hz : nm²
No vibration on Comas
Variations in amplitude and occurence
Vibration lines
No vibration in laboratory
Nothing on internal source: telescope vibrations

23. SR loss sources (2/2) Telescope vibrations:
3/25/2017
SR loss sources (2/2)
Telescope vibrations:
Main influence on Tip-Tilt modes but other excitations detected on high order modes
Vibrations not compensated for:
out of the NAOS temporal bandwidth
Strehl loss estimated to 10 % 23

24. Without turbulence, SR ~ 93 % in K with pre-compensation
Differential aberrations in CONICA and dichroics
At 1.09 mm
SR= 56%
SR =66%
With pre-compensation by NAOS deformable mirror
No compensation
At 2.15 mm
SR = 89 %
SR = 93 %
Without turbulence, SR ~ 93 % in K with pre-compensation

25. 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:
IR WFS
differential refraction, pointing model
tracking on moving object,
chopping, counter-chopping
241 scientific papers so far
=> 34.5 papers per year => Good scientific return !