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Adaptive optics for array telescopes using neural-network techniques

Abstract

IMAGES formed by ground-based telescopes are marred by atmospheric 'seeing9. The plane wavefront from an unresolved star is distorted by continually changing turbulent fluctuations in the air's refractive index. Diffraction-limited performance can in principle be recovered through the methods of adaptive optics, in which the instantaneous wavefront shape is sensed and corrected in real-time by deformable optics that cancel the distortion1,2. The highest resolution will be achieved when this technique is applied to multiple-telescope arrays. For such arrays, the biggest errors caused by seeing at infrared wavelengths are the variations in pathlength and wavefront tilt between array elements. We show here that these errors can be derived by an artificial neural network, given only a pair of simultaneous in-focus and out-of-focus images of a reference star formed at the combined focus of all the array elements. We have optimized a neural network appropriate for 2.2-μm wavelength imaging at the Multiple Mirror Telescope in Arizona. Corrections made by moving the beam-combining mirrors will largely recover the diffraction-limited profile, with a resolution of 0.06 arcsec.

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References

  1. Beckers, J. M. ESO Conf. Very Large Telescopes and Their Instrumentation Vol. 2 (ed. Ulrich, M-H.) 627–638 (European Southern Observatory, Garching bei Munchen, 1988).

    Google Scholar 

  2. Rousset, G. et al. Astr. Astrophys. 230, L29–L32 (1990).

    ADS  Google Scholar 

  3. Kolmogorov, A. Turbulence (eds Friedlander, S. K. & Topper, L.) 151–155 (Interscience, New York, 1961).

    Google Scholar 

  4. Fried, D. L. J. opt. Soc. Am. 55, 1427–1435 (1965).

    Article  ADS  Google Scholar 

  5. O'Neill, E. L. Introduction to Statistical Optics, 87–88 (Addison-Wesley, Reading, Mass., 1963).

    Google Scholar 

  6. Hardy, J. W. Proc. Soc. Photo-instrum. Engrs 1114, 2–13 (1989).

    Google Scholar 

  7. Roddier, F. Appl. Opt. 27, 1223–1225 (1988).

    Article  ADS  CAS  Google Scholar 

  8. Smithson, R. C. Lockheed Horizon 28, 24–31 (1990).

    Google Scholar 

  9. Merkle, F. ESO Conf. Very Large Telescopes and Their Instrumentation Vol. 2 (ed. Ulrich, M-H.) 656 (European Southern Observatory, Garching bei Munchen, 1988).

    Google Scholar 

  10. Paxman, R. G. & Fienup, J. R. J. opt. Soc. Am. A5, 914–923 (1988).

    Article  ADS  Google Scholar 

  11. Hege, E. K., Beckers, J. M., Strittmatter, P. A. & McCarthy, D. W. Appl. Opt. 24, 2565–2576 (1985).

    Article  ADS  CAS  Google Scholar 

  12. McCarthy, D. W., Mcleod, B. A. & Barlow, D. Proc. Soc. Photo-instrum. Engrs 1237, 496–507 (1990).

    Google Scholar 

  13. Born, M. & Wolf, E. Principles of Optics 6th edn, 416 (Pergamon, Oxford, 1984).

    Google Scholar 

  14. Chaffee, F. H. & Cromwell, R. H. Proc. Soc. Photo-instrum. Engrs 1236, 13–17 (1990).

    Google Scholar 

  15. Cromwell, R. H., Haemmerle, V. R. & Woolf, N. J. Proc. Soc. Photo-instrum. Engrs 1236, 520–529 (1990).

    Google Scholar 

  16. Lippmann, R. P. IEEE Acoustics. Speech, and Signal Processing Mag., 4–22 (April, 1987).

  17. Rumelhart, D. E., Hinton, G. E. & Williams, R. J., Parallel Distributed Processing Vol. 1 (eds Rumelhart, D. E. & McClelland, J. L.) 318–362 (MIT Press, 1986).

    Google Scholar 

  18. Allen, C. W. Astrophysical Quantities 3rd edn, 244 (Athlone, London, 1973).

    Google Scholar 

Download references

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Angel, J., Wizinowich, P., Lloyd-Hart, M. et al. Adaptive optics for array telescopes using neural-network techniques. Nature 348, 221–224 (1990). https://doi.org/10.1038/348221a0

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