A highly visible sliding plate or vane attached to a leveling staff or surveying pole. In optical leveling, the rodman slides the target up or down until the instrument operator signals it is perfectly aligned with the crosshairs, allowing for highly precise readings over long distances.
Heard on the job
Slide the target up another tenth, I can barely see it against the trees.
Related terms
Level staff
A graduated measuring rod used with a leveling instrument to determine elevation differences.
Backsight
A reading taken on a point of known coordinates or elevation to establish a reference direction.
Foresight
An instrument reading taken toward a new, unmeasured point to determine its elevation or position.