A technique in which two waves, usually of electromagnetic radiation, such as light or radio waves, are combined to produce an interference pattern: Radiation from a distant source can be analyzed by the method of interferometry in which very small angles can be accurately determined.

A technique for obtaining better images of celestial bodies by taking a series of rapid photographic exposures of the object:

Speckle interferometry enables the effect of scintillation to be minimized.

The technique of linking together several radio telescopes spaced by hundreds and even thousands of miles: The purpose of the Very Long Baseline Interferometry is to achieve very high resolution observations of distant objects, such as quasars.