Solar Adaptive Optics

High resolution observations of the Sun are of key importance in understanding fundamental astrophysical processes. Adaptive optics (AO) is an important tool that allows solar astronomers to achieve diffraction limited observations from existing ground based telescopes. AO is also a key technology required for a future 4m-class Advanced Solar Telescope (AST) that the international community of solar astronomers is planning to build. The history of the development of solar AO is reviewed and results from recent successful demonstrations of solar AO systems are presented. The main difference between solar AO and night time AO is the different, and more elaborate wavefront sensing technique that has to be applied in order to measure wavefront aberrations using solar granulation as a target. Different approaches to this problem are discussed. Multi-conjugate AO has been proposed as a technique to achieve diffraction limited resolution over a field-of-view (FOV) significantly larger than the isoplanatic patch. The Sun is an ideal object for the development and application of MCAO.

[1]  Mark A. Ealey,et al.  Xinetics low-cost deformable mirrors with actuator replacement cartridges , 1994, Astronomical Telescopes and Instrumentation.

[2]  Francois Roddier.  Wavefront curvature sensing and compensation methods in adaptive optics , 1991, Defense, Security, and Sensing.

[3]  F. Roddier,et al.  Wavefront sensing and the irradiance transport equation. , 1990, Applied optics.

[4]  J. Beckers.  The Advanced Solar Telescope: II. Technical Aspects , 1999 .

[5]  Darryl P. Greenwood,et al.  Bandwidth specification for adaptive optics systems , 1977 .

[6]  M. Vorontsov,et al.  The principles of adaptive optics , 1985 .

[7]  Mats G. Lofdahl,et al.  Wavefront sensing and image restoration from focused and defocused solar images. , 1994 .

[8]  Henri Maitre,et al.  Estimation of the adaptive optics long-exposure point spread function using control loop data: recent developments , 1997, Optics & Photonics.

[9]  R. B. Dunn,et al.  Solar feature correlation tracker for ground-based telescopes , 1989 .

[10]  E. J. Seykora.  Solar scintillation and the monitoring of solar seeing , 1993 .

[11]  Elena Masciadri,et al.  3D numerical simulations of optical turbulence at the Roque de Los Muchachos Observatory using the atmospherical model Meso-Nh , 2001 .

[12]  P. N. Brandt,et al.  Day-time seeing statistics at Sacramento Peak observatory , 1987 .

[13]  S. Wandzura,et al.  Spatial correlation of phase-expansion coefficients for propagation through atmospheric turbulence , 1979 .

[14]  Christoph U. Keller,et al.  Deconvolution of narrowband solar images using aberrations estimated from phase-diverse imagery , 1999, Optics & Photonics.

[15]  G Rousset,et al.  Optimization of a predictive controller for closed-loop adaptive optics. , 1998, Applied optics.

[16]  Richard B. Dunn.  NSO/SP adaptive optics program , 1990, Other Conferences.

[17]  Guang-ming Dai,et al.  Modal wave-front reconstruction with Zernike polynomials and Karhunen–Loève functions , 1996 .

[18]  J. Beckers.  ADAPTIVE OPTICS FOR ASTRONOMY: Principles, Performance, and Applications , 1993 .

[19]  Laird M. Close,et al.  First light for Hokupa'a: 36-element curvature AO system at UH , 1998, Astronomical Telescopes and Instrumentation.

[20]  D. Scott Acton,et al.  Solar imaging at National Solar Observatory using a segmented adaptive optics system , 1993, Smart Structures.

[21]  Richard G. Paxman,et al.  Multiframe blind deconvolution of infinite-extent objects , 1998, Optics & Photonics.

[22]  Renate Kupke,et al.  Curvature-based wavefront sensor for use on extended patterns , 1994, Astronomical Telescopes and Instrumentation.

[23]  Jacques M. Beckers.  On the relation between scintillation and seeing observations of extended objects , 1993 .

[24]  A Wirth,et al.  Solar Adaptive Optics. , 1984 .

[25]  F Roddier,et al.  Curvature sensing and compensation: a new concept in adaptive optics. , 1988, Applied optics.

[26]  Francois Rigaut,et al.  Principles, limitations, and performance of multiconjugate adaptive optics , 2000, Astronomical Telescopes and Instrumentation.

[27]  P. A. Sheppard.  Atmospheric Turbulence , 1947, Nature.

[28]  R. Noll.  Zernike polynomials and atmospheric turbulence , 1976 .

[29]  Renate Kupke,et al.  Curvature Wavefront Sensor For Solar Adaptive Optics , 2002 .

[30]  Roderick Dunn.  Adaptive optical system at NSO/Sac Peak. , 1987 .

[31]  Mats G. Lofdahl,et al.  Evaluation of phase-diversity techniques for solar-image restoration , 1996 .

[32]  Richard R. Radick.  Real Time and Post Facto Solar Image Correction , 1993 .

[33]  Richard R. Radick,et al.  Solar adaptive optics at the National Solar Observatory , 1998, Astronomical Telescopes and Instrumentation.

[34]  Eric Gendron,et al.  Astronomical adaptive optics. II. Experimental results of an optimized modal control. , 1995 .

[35]  D. Fried.  Limiting Resolution Looking Down Through the Atmosphere , 1966 .

[36]  James R. Fienup,et al.  Comparison of phase diversity and curvature wavefront sensing , 1998, Astronomical Telescopes and Instrumentation.

[37]  J. Herrmann,et al.  Cross coupling and aliasing in modal wave-front estimation , 1981 .

[38]  J. Conan,et al.  Wave-front temporal spectra in high-resolution imaging through turbulence , 1995 .

[39]  D. S. Acton,et al.  Solar imaging with a segmented adaptive mirror. , 1992, Applied optics.

[40]  Renate Kupke,et al.  Wavefront curvature sensing on extended arbitrary scenes: simulation results , 1998, Astronomical Telescopes and Instrumentation.

[41]  Richard B. Dunn,et al.  The Foucault Test for Solar Telescopes , 1987 .

[42]  O. von der Luhe.  Wavefront Error Measurement Technique Using Extended, Incoherent Light Sources , 1988 .

[43]  G Rousset,et al.  Sky implementation of modal predictive control in adaptive optics. , 1999, Optics letters.

[44]  O. V. D. Luehe,et al.  A study of a correlation tracking method to improve imaging quality of ground-based solar telescopes , 1983 .

[45]  Jacques M. Beckers,et al.  Increasing the size of the isoplanatic patch with multiconjugate adaptive optics. , 1988 .

[46]  B. Welsh,et al.  Imaging Through Turbulence , 1996 .

[47]  H. Maître,et al.  Estimation of the adaptive optics long-exposure point-spread function using control loop data , 1997 .

[48]  Dan Kiselman,et al.  Dark cores in sunspot penumbral filaments , 2002, Nature.

[49]  Jean Vernin,et al.  New approaches in atmospheric optics: generalized scidar and seeing prediction , 1998 .

[50]  Philip R. Goode,et al.  Measuring Seeing from Solar Scintillometry and the Spectral Ratio Technique , 2000 .

[51]  V. I. Tatarskii.  Ray trajectories in a medium with weak random fluctuations of refractive index , 1967 .

[52]  D. Fried.  Optical Resolution Through a Randomly Inhomogeneous Medium for Very Long and Very Short Exposures , 1966 .

[53]  A. Kolmogorov,et al.  The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers , 1991, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[54]  Eric Gendron,et al.  Astronomical adaptive optics. I. Modal control optimization. , 1994 .

[55]  Richard G. Paxman,et al.  Phase-diverse speckle reconstruction of solar data , 1994, Optics & Photonics.

[56]  W. Southwell.  Wave-front estimation from wave-front slope measurements , 1980 .

[57]  J. Hardy,et al.  Solar imaging experiment , 1980 .