Compute the pitch,roll, and focus error of the dome as it moves up the elevation rail using the theodolite data . Shim the elevation rails to correct for this error. ... The pitch and focus errors vs za change as we move 60 degrees in azimuth. We shim to minimize the errors (we can't make it go to 0). ... Using a theodolite at the rotary joint measure the deflections of the azimuth trolleys as they move around in azimuth. ... Shim the azimuth rails to minimize the deflections in azimuth. ...