The M139A1 Alignment Device, used in conjunction with the M137A3 Panoramic Telescope, verifies the boresight of the M198 howitzer. Boresighting is the means to ensure the optical fire control is properly aligned with the axis of the cannon tube. When following the specified steps, the M137A3 PanTel and M139 Alignment Device will confirm boresight of the weapon. The reticle on the M139A1 is illuminated with a battery powered LED. This LED powered version was designed as part of the ERLS program.
The M139A1 is used with the M198 Towed Howitzer, 155mm.
|M139 Alignment Device