occurs when a stimulus is flashed in one location followed by another identical stimulus flashed in another location. It refers to both the phi phenomenon
, an illusion of movement created when two or more adjacent lights blink on and off in succession, and stroboscopic motion, the movement seen in movies and television, wherein a series of quickly flashed stills creates an illusion of movement. It is also sometimes referred to as illusory motion
The term is also sometimes used in astronomy to refer to an effect which appears to cause the position of a celestial object to move (for more details see improper motion).