Abstract

A 19-segment adaptive-mirror system is currently being used on the Sacramento Peak 76-cm Tower Telescope to remove wave-front distortions resulting from atmospheric turbulence. The system has proven to be capable of substantially improving the quality of an image, at times achieving 0.33-arcsec resolution in visible wavelengths under 1–3-arcsec seeing conditions. An improvement in resolution seems to occur across a large field of view that is, at times, 30 arcsec in diameter.

© 1992 Optical Society of America

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References

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  1. J. Hardy, “Solar isoplanatic patch measurements,” in Solar Instrumentation: What’s Next?, R. B. Dunn, ed. (National Solar Observatory; Sunspot, N.M., 1980) pp. 421–433.
  2. R. C. Smithson, “A segmented active mirror for solar observations,” in Electromechanical Systems for Interaction with Optical Design, S. Gowrinathan, ed., Proc. Soc. Photo-Opt. Instrum. Eng.779, 18–22 (1987).
  3. R. H. Hudgin, “Wavefront reconstruction for compensated imaging,” J. Opt. Soc. Am. 67, 377–378 (1977).
    [CrossRef]
  4. D. S. Acton, “Real-time solar imaging with a 19-segment active mirror system,” Ph.D. dissertation (Texas Tech University, Lubbock, Tex., 1990), p. 138.
  5. R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
    [CrossRef]

1988 (1)

R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
[CrossRef]

1977 (1)

R. H. Hudgin, “Wavefront reconstruction for compensated imaging,” J. Opt. Soc. Am. 67, 377–378 (1977).
[CrossRef]

Acton, D. S.

D. S. Acton, “Real-time solar imaging with a 19-segment active mirror system,” Ph.D. dissertation (Texas Tech University, Lubbock, Tex., 1990), p. 138.

Benson, R. S.

R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
[CrossRef]

Hardy, J.

J. Hardy, “Solar isoplanatic patch measurements,” in Solar Instrumentation: What’s Next?, R. B. Dunn, ed. (National Solar Observatory; Sunspot, N.M., 1980) pp. 421–433.

Hudgin, R. H.

R. H. Hudgin, “Wavefront reconstruction for compensated imaging,” J. Opt. Soc. Am. 67, 377–378 (1977).
[CrossRef]

Peri, M. L.

R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
[CrossRef]

Smithson, R. C.

R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
[CrossRef]

R. C. Smithson, “A segmented active mirror for solar observations,” in Electromechanical Systems for Interaction with Optical Design, S. Gowrinathan, ed., Proc. Soc. Photo-Opt. Instrum. Eng.779, 18–22 (1987).

Appl. Opt. (1)

R. C. Smithson, M. L. Peri, R. S. Benson, “Quantitative simulations of image correction for astronomy with a segmented active mirror,” Appl. Opt. 19, 1615–1620 (1988).
[CrossRef]

J. Opt. Soc. Am. (1)

R. H. Hudgin, “Wavefront reconstruction for compensated imaging,” J. Opt. Soc. Am. 67, 377–378 (1977).
[CrossRef]

Other (3)

D. S. Acton, “Real-time solar imaging with a 19-segment active mirror system,” Ph.D. dissertation (Texas Tech University, Lubbock, Tex., 1990), p. 138.

J. Hardy, “Solar isoplanatic patch measurements,” in Solar Instrumentation: What’s Next?, R. B. Dunn, ed. (National Solar Observatory; Sunspot, N.M., 1980) pp. 421–433.

R. C. Smithson, “A segmented active mirror for solar observations,” in Electromechanical Systems for Interaction with Optical Design, S. Gowrinathan, ed., Proc. Soc. Photo-Opt. Instrum. Eng.779, 18–22 (1987).

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Figures (14)

Fig. 1
Fig. 1

Block diagram of the AO system.

Fig. 2
Fig. 2

19-segment adaptive mirror.

Fig. 3
Fig. 3

Piezoelectric triad.

Fig. 4
Fig. 4

Hartmann wave-front sensor.

Fig. 5
Fig. 5

Block diagram of the servoloop control for a single segment.

Fig. 6
Fig. 6

White-light interferogram of the adaptive mirror. Here the phase network is compensating for 12 waves of tilt in the wave front.

Fig. 7
Fig. 7

Optical layout.

Fig. 8
Fig. 8

MTF’s of the corrected (solid curve), uncorrected (short-dashed curve), and perfect (long-dashed curve) imaging systems.

Fig. 9
Fig. 9

(a)–(d) Pairs of corrected and uncorrected images of a small pore taken in various visibility conditions. Each corrected image (top) was taken simultaneously with the corresponding uncorrected image (bottom). The picture pairs are arranged in order of decreasing quality of seeing conditions. The field of view is 9 arcsec2. The telescope aperture was 63.5 cm in diameter, the wavelength was 480 nm, and the exposure time was 5 ms.

Fig. 10
Fig. 10

Corrected–uncorrected image pair printed at (a) original (b) medium, and (c) high contrast. The tick marks are at 1-arcsec intervals. Note that the corrected image (top) shows features as small as 0.25 arcsec that are not visible in the uncorrected image. The telescope aperture was 63.5 cm in diameter, the wavelength was 480 nm, and the exposure time was 5 ms.

Fig. 11
Fig. 11

(a)–(f) Evolution of a subgranule, with images taken sequentially 5 s apart. The contrast has been artificially increased to show the high-frequency information. The field of view is 3.65 arcsec2. In (f) the subgranule is only 0.33 arcsec wide. The images were taken in ~ 2-arcsec seeing conditions.

Fig. 12
Fig. 12

Correction across a wide field 24 arcsec in diameter; (a) corrected image and (b) uncorrected image. The tick marks are at 1-arcsec intervals. The telescope aperture was 32 cm in diameter, the wavelength was 520 nm, and the exposure time was 17 ms.

Fig. 13
Fig. 13

Digitized video images in (a) poor seeing conditions, (b) average seeing conditions, and (c) good seeing conditions. The corrected images are on the top and the uncorrected images are on the bottom. The tick marks are at 1-arcsec intervals. The telescope aperture was 32 cm in diameter, the wavelength was 520 nm, and the exposure time was 17 ms.

Fig. 14
Fig. 14

Magnitude of the Fourier spectrum of the corrected images in Fig. 12 divided by that of the uncorrected images.

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