sentences:  This technique works by superposing ("interfering") the signal waves from the different telescopes on the principle that waves that coincide with the same phase will add to each other while two waves that have opposite phases will cancel each other out.This creates a combined telescope that is the size of the antennas furthest apart in the array.In order to produce a high quality image, a large number of different separations between different telescopes are required (the projected separation between any two telescopes as seen from the radio source is called a "baseline") – as many different baselines as possible are required in order to get a good quality image.