Install the reference reticle. This is done with Argus on its stand. The periscope and fibers are all withdrawn to the home position to get them out of the way. The reticle is installed in the Argus focal plane from underneath. The reticle is mounted on an aluminum plate with captive mounting screws and locating pins.
Installation is straightforward and obvious.
Next, a special viewing device must be installed to permit viewing the lines on the reticle on a TV screen. The viewing system is installed in place of the periscope head. Once installed, it can roam around the field using the periscope motion control system and position itself under all the parts of the reticle grid. This is the center of the field. If the model is perfect it will go exactly to the intersection.