Right side up, not inverted. Optically correct left to right. TC-II 90 Degree crosslines with equally spaced divisions and 2 concentric circles for vertical and horizontal alignment. No extra illumination is necessary. It is important never to change the cross hair reticle adjustment on the Cathetometer while the instrument is in use.
Otherwise errors result.
Attach Cathetometer to a Height Gauge. Place Height Gauge on surface plate or any other level flat surface. Looking through eyepiece, turn knurled knob by the eyepiece until the cross hair is in sharp focus. Adjust height approximately for the Cathetometer to line up with the object to be checked. Rotate knurled eyetube in front of Cathetometer until object is in sharp focus.