Abstract: An orienting device for a perforator or the like to permit directing the tool at a selected angle relative to a ferrous element such as an adjacent casing string, and further an orienting device which is resistant to signal reversal resulting from ferrous non-uniformities in the region of the wellbore, the orienting device comprising an electromagnetic field source producing an alternating electromagnetic field and a receiver array longitudinally spaced from the electromagnetic field source, the disposition of the receiver array being such that the voltages induced therein vary differentially with the angle presented by the proximate ferrous elements by reason of the distortion of the otherwise axially symmetrical field. Electronic circuitry is provided to convert the differential voltages to a signal which is received at the surface and caused to register the orientation angle. A motor section is provided to rotate the device.