P120FB13: Orthographic close-up of center of Target and Pickoff mirror.
The Target has four quadrants, Red, White, Blue, and Green, the 1st through 4th quadrants as you look at the face of the target. The fiducial marks at the center are 0.05 mm wide by 1 mm long. Note the 45 degree mitered finishes at the center. The fiducial colors, from the east, CCW, are magenta, gray, cyan, and yellow.
The magenta, green and red to the left is the Pick-off Mirror. The magenta and green are facets on the reflective surface for the upper bands. The red at the base of the green is the notch in the center of the Pick-off Mirror. The bottom part of the Pick-off Mirror is red in this view and is in front of the Target.