A system and method for providing information for performing a registration correction for artillery employs two spaced apart optical imaging systems associated with a processing system. Outputs from the two imaging systems are monitored to detect potential shell trajectory events and then correlated to eliminate potential shell trajectory events not viewed by both optical imaging systems. Locations are determined for potential shell trajectory events viewed by both optical imaging systems. Shell firing data relating to firing of at least one shell is provided to determine at least one predicted trajectory time point for the shell, and this is used to identify a corresponding detected shell trajectory event. The time and location of the detected shell trajectory event can then be used in determining a registration correction for the artillery