CittertZernike
The Cittert–Zernike theorem, often cited as the Cittert–Zernike theorem, is a foundational result in optical coherence theory that relates the spatial coherence of light from an incoherent, distant source to the source’s angular brightness distribution. It was independently derived in the 1930s by Anton van Cittert and Frits Zernike and has since become central to the practice of astronomical interferometry and aperture synthesis.
In its standard form, the theorem states that for a quasi-monochromatic, spatially incoherent source observed in
Applications of the theorem include reconstruction of an object's image from interferometric data, enabling aperture synthesis