Spatial heterodyne spectroscopy is a technique used in astronomy and remote sensing to study the spectra of objects in space. It involves using multiple interferometers to create interference patterns that can be analyzed to determine the spectral information of the object being observed. This technique allows for high spectral resolution and sensitivity, making it useful for studying faint or distant sources of light. It is also well-suited for studying extended sources, such as planetary atmospheres or interstellar clouds.