Abstract: An apparatus for measuring the alignment of two or more adjacent targets while the targets are in motion is provided. The alignment measuring apparatus includes a plurality of alignment scanners, each adapted to detecting the arrival of an associated target. A speed scanner is spaced apart from the alignment scanner for detecting said first one of the targets. First timing means are provided for measuring a first time differential indicative of the time delay between detection of the leading and trailing targets by the alignment scanners to provide a measurement proportional to the misalignment between the targets.