Abstract

Low spatial frequencies of atmospheric turbulence are especially troublesome to astronomers because the phase distortions that these frequencies cause have a large amplitude. We have begun experiments at the Multiple Mirror Telescope to remove these errors with tip, tilt, and piston control of pieces of the wave front that are defined by the telescope’s six 1.8-m primary mirrors. We present long-exposure images that were recorded at the telescope with a resolution of as high as 0.08 arcsec under piston control, and 0.32 arcsec under tilt control, by use of an adaptive instrument designed to restore diffraction-limited imaging in the near infrared. Of particular importance for high-resolution imaging is the control of the piston or the mean phase errors between the segments. These errors can be calculated from the Fourier transform of the short-exposure combined-focus image, but the accuracy of the reconstructed wave front depends critically on the signal-to-noise ratio of the data. We present a theoretical analysis of the effects of photon and detector read noise on the derived piston errors and computer simulations of wave-front reconstructor algorithms. We find that a Wiener filter combined with nonlinear weighting of the piston errors minimizes the impact of noise. Finally, we summarize expected improvements to our system and discuss the application of these techniques to forthcoming large telescopes.

© 1994 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Adaptive optics for array telescopes using piston-and-tilt wave-front sensing

P. Wizinowich, B. McLeod, M. Lloyd-Hart, J. R. P. Angel, D. Colucci, R. Dekany, D. McCarthy, D. Wittman, and I. Scott-Fleming
Appl. Opt. 31(28) 6036-6046 (1992)

Adaptive optics for diffraction-limited infrared imaging with 8-m telescopes

D. G. Sandler, S. Stahl, J. R. P. Angel, M. Lloyd-Hart, and D. McCarthy
J. Opt. Soc. Am. A 11(2) 925-945 (1994)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (12)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (45)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription