Abstract: A sighting cap is provided for the stationary housing of a rotating laser beam transmitter. The sighting cap has two pairs of legs respectively defining vertical sighting slots. Two of the sighting slots are aligned with the X axis of the laser beam positioning mechanism and the other two slots are aligned with the Y axis of the laser beam positioning mechanism. A sighting post is established in the work area to define a line between the axis of rotation of the rotating laser beam transmitter and the sighting post which is parallel to the X or Y axis of a previously conducted survey of the work area. Sighting through the sighting slots, accompanied by adjustment of the angular position of the stationary housing permits the precise alignment of the sighting slots, hence the positional axis of the laser beam plane adjusting mechanism, in parallel relationship with the survey axes.