This paper describes a series of perception experiments directed towards developing a model of moving target detection. The experiments systematically and precisely varied target size and speed, and found that the final probability of detection is primarily dependent on the size and did not depend on the speed. This, coupled with the finding that time to detect varied inversely with angular velocity as seen by the observer, indicated that the angular distance traveled across the display screen described the perception threshold for detection of a moving target. These findings, especially that the primary figure of merit associated with the detection of moving targets was angular displacement, have not previously been reported, apparently because earlier experiments confounded variables and made it difficult to separate the effect of target speed and time to detect on the overall psychophysical response. This new view holds promise for providing a fruitful lens through which to view the phenomenology of detection of moving targets and should assist in establishing new insights into the nature of motion perception.