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Speckle v Non-Redundant Masking

Published online by Cambridge University Press:  19 July 2016

C.A. Haniff
C.A. Haniff*
Affiliation:
MRAO, Cavendish Laboratory, Madingley Road, Cambridge, CB3 OHA, UK

Abstract

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Unlike their radio counterparts, optical astronomers have paid relatively little attention to the role of the aperture function when designing their high resolution imaging experiments. This is despite the fact that it can be easily modified with the use of a suitable pupil plane mask. While the defining characteristics of the two most favoured pupil configurations have never been in doubt – negligible atmospheric noise in the case of a non-redundant configuration of small holes and high photon rates for a filled pupil – the relative merits of these two choices in terms of imaging performance in the presence of turbulence appear not to have been carefully investigated until very recently.

Most existing comparisons of fully-filled aperture (FFA) and non-redundant mask (NRM) based imaging strategies appear to have ignored a number of fundamental and practical difficulties that are often encountered in practice. In the intermediate regime, between very high and very low light levels, that characterizes most astrophysical applications hybrid imaging schemes seem most profitable. These utilize partially-redundant pupil geometries that combine the advantages of redundancy at low light levels without incurring the penalties associated with fully redundant beam recombination. Such pupil geometries are also useful in reducing the level of systematic effects that often plague speckle imaging experiments.

Keywords

Specklenon-redundant-maskingaperture distributionspartially redundant pupils
Type
Aperture Distributions
Information
Symposium - International Astronomical Union , Volume 158: Very High Angular Resolution Imaging , 1994 , pp. 317 - 325
Copyright
Copyright © Kluwer 1994 

References

[1] See. e.g., 1988, Proc NOAO-ESO Conference on ‘High-resolution imaging by interferometry’ Merkle, F. (ed) (ESO: Garching bei München).Google Scholar
[2] Kulkarni, S.R.: 1988, ‘The non-redundant mask technique: theory and practice’, Proc NOAO-ESO Conference on ‘High-resolution imaging by interferometry’ Merkle, F. (ed) (ESO: Garching bei München) 595.Google Scholar
[3] Pearson, T.J. and Readhead, A.C.S.: 1984, ‘Image formation by self-calibration in radio astronomy’, Ann. Rev. Astron. Astrophys. 22, 97.Google Scholar
[4] Wieringa, M.H.: 1992, ‘An investigation of the telescope based calibration methods redundancy and self-cal’, Experimental Astronomy 2, 203.CrossRefGoogle Scholar
[5] Bartelt, H., Lohmann, A.W., and Wirnitzer, B.: 1984, ‘Phase and amplitude recovery from the bispectrum’, Applied Optics 23, 3121.Google Scholar
[6] Lannes, A.: 1989, ‘Backprojection mechanisms in phase-closure imaging: bispectral analysis of the phase-restoration process’, Experimental Astronomy 1, 47.CrossRefGoogle Scholar
[7] See. e.g., Roddier, F.: 1988, ‘Interferometric imaging in optical astronomy’, Physics Reports 170, 97.CrossRefGoogle Scholar
[8] Roddier, F. and Mariotti, J.-M.; 1993, ‘Aperture-plane Interferometry’, SPIE-ERIM Infrared and Electro-optics Handbook 8, in press.Google Scholar
[9] Buscher, D.F.: 1988, ‘Aperture masking and speckle masking: a comparison of their signal-to-noise ratios’, Proc NOAO-ESO Conference on ‘High-resolution imaging by interferometry’ Merkle, F. (ed) (ESO: Garching bei München) 613.Google Scholar
[10] Kulkarni, S.R., Prasad, S., and Nakajima, T.: 1991, ‘Noise in optical synthesis images. II. Sensitivity of an n C 2 interferometer with bispectrum imaging’, J. Opt. Soc. Am. A 8, 499.Google Scholar
[11] See. e.g., Buscher, D.F.: 1993, ‘Direct Maximum-Entropy image reconstruction from the bispectrum’, these proceedings. Google Scholar
[12] Haniff, C.A. and Buscher, D.F.: 1992, ‘Diffraction-limited with partially redundant masks – 1. Infrared imaging of bright objects’, J. Opt. Soc. Am. A 9, 203.Google Scholar
[13] Buscher, D.F. and Haniff, C.A.: 1993, ‘Diffraction-limited with partially redundant masks – 2. Optical imaging of faint sources’, J. Opt. Soc. Am. A in press.Google Scholar
[14] Aime, C. and Roddier, F.: 1977, ‘One-dimensional stellar and solar speckle interferometry’, Opt. Commun. 21, 435.CrossRefGoogle Scholar