Advanced Astronomy - 14: Speckle Interferometry and Aperture ...

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Speckle Basics - Theory ASTR278 Mike Ireland Recap Early Masking Speckle Interferometry Aperture Masking Summary The Fourier transform of the image is the Fourier transform of the object multiplied by the OTF: I(α) = O(α) ⊗ PSF (α) (1) F[I](u) = F[O](u) × OTF(u) (2) The phase of the OTF varies with atmospheric phase, but we assume that the modulus of the OTF is constant: 〈|F[O](u)| 2 〉 = 〈|F[I](u)| 2 〉/|OTF(u)| 2 (3) Finally, we estimate the OTF from the Fourier transform of a point source (i.e. a calibration star): |OTF| 2 = 〈|F[I pointsource ](u)| 2 〉 (4)
Speckle Basics - In Practice ASTR278 Mike Ireland Recap Early Masking Speckle Interferometry Aperture Masking Summary Record many frames rapidly. Take the power spectum of each frame and average. Divide the power spectrum of a target by the power spectrum of a point source. Fit a model (e.g. a binary star) to the true Fourier transform of the object.
Page 1 and 2: ASTR278 Mike Ireland Recap Early Ma
Page 3 and 4: Outline ASTR278 Mike Ireland Recap
Page 5 and 6: Fizeau and Michelson ASTR278 Mike I
Page 7: Enter Antoine ASTR278 Mike Ireland
Page 11 and 12: Shift and Add ASTR278 Mike Ireland
Page 13 and 14: Sparse Aperture-Masking ASTR278 Mik
Page 15: Summary ASTR278 Mike Ireland Recap

Advanced Astronomy - 14: Speckle Interferometry and Aperture ...

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