Aligning on-line checking facility for a satellite laser ranging station

The arrangement takes into account that each reflecting surface in the laser cavity, as well as in the deflection chain, gives a return pinhole image in the aligning instrument (AI) eyepiece reticle. It is noted that the AI must first be aligned with the mirrors of the power laser cavity to make the center of its reticle represent the power laser axis. The deflection of this axis along the vertical can then be performed by adjusting one of the multilayer-coated mirrors while observing the pinhole image reflected by HgP. A trial-and-error procedure is then followed to put the rotation axis of the mount along the vertical, alternately adjusting its leveling footscrews and one of the auxiliary plane mirrors (using its reference return image) while rotating the instrument around its vertical axis. The same procedure is then repeated for the remaining beam path until all return images overlap and remain stationary in the center of the reticle for any rotation around the X and Z axes.