Astronomical imaging can be broadly classified into two types. The first type is amplitude interferometry, which includes conventional optical telescopes and Very Large Baseline Interferometry (VLBI). second intensity relies on Hanbury Brown Twiss-type measurements. At frequencies, where direct phase measurements are impossible, interferometry has an effective numerical aperture that limited by...

The current status of the high spatial resolution imaging interferometry in optical astronomy is reviewed in the light of theoretical explanation, as well as of experimental constraints that exist in the present day technology. The basic mathematical interlude pertinent to the interferometric technique and its applications in astronomical observations using both single aperture, as well as dilu...