A characteristic unique to artillery
in which the fire is adjusted out of sight of the guns. An observer in proximity to the target reports the target's estimated position which becomes the impact point of the first rounds. From the first impact the oberver requests adjustments, e.g. right 400 add 2000. The guns aim at artificial aiming points installed by the crew of each gun.
From this, it must be said that in direct fire the target is seen and aimed at from the gun.