Speckle Imaging: a boon for astronomical observations
  The speckle imaging is a photographic technique that resolves objects viewed through severely distorted media. The results are insensitive to the errors caused by apparent size of the isoplanatic patch and the telescope aberrations. In this article, a short descriptions of the atmospheric turbulence and its effect on the flat wavefront from a stellar source is presented; the shortcomings of the conventional long-exposure images in the presence of Earth's atmosphere are discussed. The advantages of the speckle interferometric technique over conventional imaging are enumerated. The technical details of the method, basic Fourier optics, data analysis procedures are also described. 
S K Saha