Occulters are devices or objects used in astronomy to block the light coming from a star or other celestial body in order to observe the dimmer objects or features nearby. They are used to study things like exoplanets, debris disks, and other faint objects that are otherwise obscured by the bright light of a star. Occulters can come in various forms, such as disks, masks, or other shapes that are strategically placed in the telescope's field of view to create a shadow and block out the unwanted light. This technique is particularly useful in the search for exoplanets and understanding the structure of planetary systems.