HIGH RESOLUTION & CONTRAST

Imaging

F. Pedichini

PARSEC: 3.26 ly

1 Pc

3 Pc

1 A.U.1 A.U. 1 A.U.1 A.U.

1 arcsec

2 arcsec

EXO_Planets @ 10 pc

5 A.U.

3 A.U.

1 A.U.

10 pc100 mas

500 mas

300 mas

1rad = 206265 arcsec[1 mas = 1e-3 arcsec]

Airy disc @ telescope [mas] :

1.22λ/D

Lambda [µm] Mirror 0.1 Mirror 1.0 Mirror 10 Mirror 40 Mirror 100

0.35 880 88 8.8 2.2 0.8

0.65 1634 163 16.3 4.0 1.6

2.5 6284 628 62.8 15.7 6.3

10 25136 2513 251.3 62.8 25.13

Airy disc @ 8.2 m, high contrast:

Sun flux @ 10pc = 1.5e9 γ/s [R band]

[mas]

Peak normalized flux

1.22λ/D @ 630 nm ~ 18 mas

Sun flux @ 10pc = 1.5e9 γ/s [R band]

Jupiter flux @ 10pc, 5A.U. = 5.0 γ/s [R band]

Jupiter flux @ 10pc, 1A.U. = 125 γ/s Jupiter flux @ 10pc, 0.5A.U. = 600 γ/s

Planet contrast vs Sun distance:

[mas]

Diffraction profile for 8.2 m telescope

3e-2

8e-3

8e-4

Detection is not Contrast !

𝑆𝑁𝑏

(𝑡)=𝑆 ∙𝑡

√(𝑆+𝑏 ) ∙ 𝑡+𝑅𝑂𝑁S/N is intrinsic in photon statistics

Detection is not Contrast (the Math) !

( 𝑆𝑁 )𝑓

∝𝑓 ∙𝑡𝑒𝑥𝑝

√ 𝑓 ∙𝑡𝑒𝑥𝑝+𝑅𝑂𝑁2;

⇓

𝑁∝√𝑆 ;𝑆𝑡𝑎𝑟 +𝑝≅ 𝑆𝑡𝑎𝑟 ;

( 𝑆𝑁 )𝑝

∝𝑝 ∙𝑡𝑒𝑥𝑝

√𝑆𝑡 𝑎𝑟 ∙ 𝑡𝑒𝑥𝑝+𝑅𝑂𝑁 2⟹𝑝 ∙√ 𝑡𝑒𝑥𝑝

𝑆𝑡𝑎𝑟

Airy profile flux normalized

Detection !texp[s] 0.5 A.U. 1 A.U. 5 A.U.

1 707 223 22

10 2236 707 71

100 7071 2236 224

1000 22360 7071 707

Sun flux @ 10pc = 1.5e9 γ/sJupiter flux @ 10pc, 5A.U. = 5 γ/s

Jupiter flux @ 10pc, 1A.U. = 125 γ/s

𝒏𝒐𝒊𝒔𝒆=√𝒔𝒖𝒏𝒇𝒍𝒖𝒙 (𝑨 .𝑼 .) ∙𝒕𝒆𝒙𝒑

1 10 100 10001

10

100

1000

10000

100000

1000000

Texp [s]

Flux , noise [γ]

5 A.U.

0.5 A.U.

1 A.U.

Detection !

1 10 100 10001

10

100

1000

10000

100000

1000000

Terra, terra….

Jupiter

𝑟𝐽𝑟𝑇

≅ 10⟹10− 2 𝑓𝑙𝑢𝑥

mag=5

Simple telescope optics:

PUPIL plane

IMAGE plane IMAGE plane

PUPIL plane

Less Simple telescope optics:

PUPIL plane

IMAGE plane IMAGE plane

PUPIL plane

OCCULTING DISK

Lyot Coronagraph telescope optics:

PUPIL plane

IMAGE plane IMAGE plane

PUPIL plane

OCCULTING DISK

LYOTSTOP

Lyot Coronagraph gain 100 in contrast:

Coronagraph !texp[s] 1 A.U. 5 A.U. Terra 1A.U.

1 87 4 1.25

10 274 12 12.5

100 866 39 125

1000 2739 122 1250

Sun flux @ 10pc = 5e9 γ/sJupiter flux @ 10pc, 5A.U. = 5 γ/s

Terra flux @ 10pc, 1A.U. = 1.3 γ/s

√𝒔𝒖𝒏𝒇𝒍𝒖𝒙 (𝑨 .𝑼 .)

1 10 100 10001

10

100

1000

10000

100000

1000000

𝒏𝒐𝒊𝒔𝒆=√𝒔𝒖𝒏𝒇𝒍𝒖𝒙 (𝑨 .𝑼 .) ∙𝒕𝒆𝒙𝒑

Texp [s]

Flux , noise [γ]

5 A.U.

1 A.U.

Coronagraph Detection

1 10 100 10001

10

100

1000

10000

100000

1000000

Lyot gaussian Coronagraph gain ~1e4 in contrast:

NO OBSTRUCTION

SECONDARY 11%OBSTRUCTION

Seeing @telescope:

ℱ (𝑟 )=𝑒−( 𝑟𝜃 )𝛾

𝛾≅ 2 𝜃=𝐹𝑊𝐻𝑀2.3 𝐹𝑊𝐻𝑀≫600𝑚𝑎𝑠

Detection; FWHM size is crucial !

r=25 r=15 r=10

r=5

Noise levelr.m.s. 33

Integral Signal10000

S/N=4S/N=34

S/N=1S/N=17

S/N=0.5S/N=11S/N=6

S/N=?

S/N [peak]S/N [integral]

Seeing @ 8.2 m, low contrast:

Flux normalized to 1

[mas]

600 mas FWHM seeing

Airy profile

Seeing profile FWHM=1”

Strehl, Kolmogorov and Marechal:

𝑆=𝑒−(2 𝜋𝜎 (𝐶𝑛❑

2 )

𝜆 )2

𝜎=0 ;𝑆=1 𝜎=107 ;𝑆=0.32

𝜆=630 [𝑛𝑚 ] 𝜆=630 [𝑛𝑚 ]

the Large Binocular Telescope• Aperture diameter [m] 2 x 8.4 (f# 15)• Wavelenght [µm] 0.32 ÷ 10• Mount control Alt-Az on oil pad• Lens profile error[nm] <50 (active and adaptive optic )• Image blurring [arcsec] 0.3 ÷ 0.9 (0.015 diff. limit)• Adaptive optics facility embedded in the secondary mirror• Location Mount Graham (Arizona) 3200 m

the Large Binocular Telescope

Adaptive Optics basic:MTF

N.C.P.A.

Experimental PSF (LBT FLAO results):

H band[1.6µ]

Esposito et al. SPIE 2011

Strehl vs guide star (LBT FLAO results):

Esposito et al. SPIE 2011

HIP76041 750nm-10nm seeing 1” 600 modino optics -> scale = 7.2mas/pix

Ghost

E. Pinna, priv. com.

HR 8799 infrared light from ExoPlanets:

Esposito et al. A&A 549, 2013

PSF reconstruction… where are the planets here ?

Theoretical limit for 8.2m @ 650nm(texp 3600 s + A.O. σ 80 nm + Lyot-coro)

10 pc 5 pc

1 J

4 J

10 J

50 J

Angular Differential Imaging:RA = 0° RA = 20° RA = 45°

PA = 0° PA = 20° PA = 45°

V-SHARK-Forerunner: 600nm A.O. at 1600 f.p.s. (goal 16÷17 mas. resolution)

Io moons of Jupiter

Simulated image of

X

Y

Z

V-SHARK CORONAGRAPH optical layout

V-SHARK in 3d:

Hot Stuff (Advanced Adaptive Optics)

Adaptive Optics can work at visible; running fast,saving the errors and doing blind de-convolution you get this…!

Courtesy of S. Jefferies (Maui Air Force Lab)

No A.O. at 1.2m telescope!

Applied Optics, Vol. 48, Issue 1, pp. A75-A92 (2009)http://dx.doi.org/10.1364/AO.48.000A75

Courtesy of S. Jefferies (Maui Air Force Lab)

Is this possible….?

880 nm3.6 meter telescope1.22 λ/D = 61mas

10 cm @ 560 km = 36mas

Next future LBTI vs EELT:

21 m baseline2 x 1000÷4000 actuators

Ro=13÷6 cm

37 m baseline4000 actuators

Ro=30 cm

NGS vs LGS :

che la Forza sia con Voi !

grazie per l’attenzioneCourtesy of D. Bonaccini (ESO)