A visualization of the prediscovery algorithm. The orbital uncertainty from postdiscovery observations is propagated back in time to the survey to identify images and search regions within those images (black ellipses). Sources detected in the search regions are candidate prediscoveries. Each candidate source corresponds to a trial orbit, which is propagated to the other images to look for coincident detections. A true prediscovery will result in multiple detections along a single physical orbit.