ABSTRACT
E{ Y(x + u,y + v, t) Y(x,y, t)} = J J f(o:, (3)ei(un+vd)do: d(3 (2.1) where ( o:, (3) are the coordinates of the source of interest in the sky and/( a, (3) is its brightness distribution as a function of (a, (3). In other words, the Fourier transform is the quantity observed. The result Eq. (2.1) is known as the van Cittert-Zernike Theorem, see Born and Wolf(\964).
