1. Viewing the Universe through distorted lenses: Adaptive optics in astronomy Steven Beckwith Space Telescope Science Institute & JHU

2. 12/6/03Astronomical Adaptive Optics2 Atmospheric turbulence stratosphere tropopause Heat sources within dome boundary layer ~1 km 10-12 km wind flow over dome Log turbulence, C n 2 Wind shear Wind shear -18-17-16-15-14 0 10 20 km Courtesy Claire Max, Center for Adaptive Optics r 0 ~ 40cm (µm) 2 v wind ~ 10 m/s

3. 12/6/03Astronomical Adaptive Optics3 How are stellar images created? Even the largest ground-based astronomical telescopes have no better resolution than an 8" telescope! Lick Observatory, 1 m telescope 10s exposure 10ms exposure Diffraction-limit Speckles (each is at diffraction limit of telescope) ~ 1 arc sec ~ 0.1 arcsec ~ / D Courtesy Claire Max, Center for Adaptive Optics Typical time scales ~ 10 ms

4. 12/6/03Astronomical Adaptive Optics4 Adaptive Corrections

5. 12/6/03Astronomical Adaptive Optics5 Mauna Kea telescopes Gemini N CFHT Keck 1&2 Subaru

6. 12/6/03Astronomical Adaptive Optics6 The Gemini AO system: movie

7. 12/6/03Astronomical Adaptive Optics7 AO correction of a star

8. 12/6/03Astronomical Adaptive Optics8

9. 12/6/03Astronomical Adaptive Optics9 ALTAIR: Gemini AO system

10. 12/6/03Astronomical Adaptive Optics10 Examples of AO corrected images R136, Adonis

11. 12/6/03Astronomical Adaptive Optics11 The Center of the Milky Way

12. 12/6/03Astronomical Adaptive Optics12 Faint companions to stars Liu et al. 2003, Astrophysical Journal, in press 0.06 M sun (48 M jup ) L dwarf companion HR 7672; 14 AU from star Gemini/Hokupa’a

13. 12/6/03Astronomical Adaptive Optics13 Lockheed/Itek system at Sac Peak (1980’s); FWHM gain ~4. Sac peak/Big Bear and 3 other facilities in the world. –Typically 70 cm class telescopes –AO 24: 1998-2000 –AO 76: 12/2002-now Different constraints (correlators) Limitation: Field of view ⇨ MCAO programs in the work Imaging the Sun: 1kW m -2

14. 12/6/03Astronomical Adaptive Optics14  iso 10 km D tel Isoplanatic angle,  iso Limitations Isoplanatic angle: ~30 ” (  µm) 2 Sky coverage: ~2% Wavelength range: > 1 µm Anisoplanatism: image quality deteriorates farther from guide star AO now AO~2009 Space now2009 HST r 0 ~40cm (µm) 2

15. 12/6/03Astronomical Adaptive Optics15 No AO With AO No AO With AO Intensity Future promise Artificial guide stars: sodium laser-induced fluorescence Multi-conjugate adaptive optics (MCAO) Adaptive secondary mirrors: simplified optical train Very high order corrections: ~10,000 actuator mirrors

16. 12/6/03Astronomical Adaptive Optics16 Tomographic reconstruction: multiple stars X-ray tomography atmospheric tomography to use in astronomy