Our understanding of the cosmos is shaped by what we are able to observe in the sky. Resolving progressively smaller astrophysical structures requires instruments with increasingly high angular resolution. However, even an ideal telescope is limited by nature through diffraction, which ties its resolving power to the diameter of its collecting aperture. To circumvent this limitation, a technique known as interferometry is employed, in which angular resolution is determined by the separation between distinct telescopes rather than by the size of a single dish.
In this seminar, we discuss the concepts of interference, coherence, and visibility amplitude, which form the foundation of interferometric observations. We also introduce aperture synthesis, the method by which images of astrophysical sources are reconstructed from their interferometric signatures. Finally, we comment on some applications of these results to the physics of compact objects.