Coherence theory of a radio telescope

Carter, W.; Somers, L. E.

doi:10.1109/tap.1976.1141422

Cited by 5 publications

(3 citation statements)

References 18 publications

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“…The strength of this technique used in this work is in its ability to handle partially-coherent radiation (Withington et al 2003;Carter & Somers 1976). Though coherent analysis of electromagnetic systems are useful and informative (eg.…”

Section: Discussionmentioning

confidence: 99%

“…The strength of the technique used in this work is in its ability to handle partially coherent radiation (Withington et al 2003;Carter & Somers 1976). Though coherent analysis of electromagnetic systems are useful and informative (e.g., Wollack et al 2006 and references therein), the second-order statistical corre-lations introduced by these systems are not directly accessible.…”

Section: Discussionmentioning

confidence: 99%

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Diffraction Considerations for Planar Detectors in the Few-Mode Limit

Chuss¹,

Wollack²,

Moseley³

et al. 2008

PUBL ASTRON SOC PAC

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ABSTRACT. Filled arrays of bolometers are currently being employed for use in astronomy from the far-infrared through millimeter portion of the electromagnetic spectrum. Because of the large range of wavelengths for which such detectors are applicable, the size of a pixel (p) relative to the wavelength (λ) will vary according to the specific application of a given available technology. As the pixel size becomes comparable to a wavelength of the absorbed radiation, correlations in the radiation field at the pixel can affect the imaging properties of the system independent of the correlations introduced by the front-end optics. We study the dependence of image fidelity and induced polarization on the size of the pixel by employing a formalism in which diffraction due to the pixel boundary is treated by propagating the second-order statistical correlations of the radiation field through an optical system. We construct simulated polarized images of square pixels for various ratios of p=λ. For the limit in which few modes are supported by the pixel (p=λ ≲ 1), we find that the diffraction due to the pixel edges is nonnegligible and hence must be considered along with the telescope diffraction pattern in modeling the ultimate spatial resolution of an imaging system. For the case in which the pixel is over-moded (p=λ ≫ 1), the geometric limit is approached as expected. This technique provides a quantitative approach to understand and optimize the imaging properties of planar detectors in the few-mode limit.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Diffraction Considerations for Planar Detectors in the Few-Mode Limit

Chuss¹,

Wollack²,

Moseley³

et al. 2008

PUBL ASTRON SOC PAC

View full text Add to dashboard Cite

show abstract

“…Gull and Daniel31 tried maximizing Q2 while replacing constraint (8) 1=1 (12) This does not exploit the antenna -dependence of the phase errors. Unlike (8), (12) does not define a convex subspace of solutions, so a unique local maximum of Q2 cannot be guaranteed; a search algorithm can be expected to converge to a local maximum which depends on its starting point, the "initial guess" map.…”

Section: Large Phase Errorsmentioning

confidence: 99%

<title>Fourier Reconstruction Techniques In Radio Astronomy: A Review</title>

D'Addario

1980

SPIE Proceedings

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The Fourier synthesis technique of image formation has been in use in radio astronomy since the 1950's.Interferometric measurements provide values of the complex Fourier transform of a brightness distribution at a finite set of spatial frequencies, and it is required to reconstruct the brightness distribution.Originally, the reconstruction consisted simply of computing the inverse transform with the values at all unmeasured spatial frequencies set to zero.With good spatial frequency coverage, this often gives a satisfactory result.However, observations are often made with limited coverage. Also, the increasing sensitivity of radio telescopes has led to a demand for larger dynamic range in the images.There has therefore been an effort to develop improved imaging techniques; these are reviewed here.T.Background discussion

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Three Different Kinds of Fraunhofer Approximations.

Carter

1990

Journal of Modern Optics

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Coherence theory of a radio telescope

Cited by 5 publications

References 18 publications

Diffraction Considerations for Planar Detectors in the Few-Mode Limit

Diffraction Considerations for Planar Detectors in the Few-Mode Limit

<title>Fourier Reconstruction Techniques In Radio Astronomy: A Review</title>

Three Different Kinds of Fraunhofer Approximations.

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