P120FB07: Target off. Black is at depth greater than 10, viewing past the Pick-off Mirror. A depth of 8 is required for 2 lenses, the filter, and beamsplitter, each of which have 2 refractive surfaces. The Green is gone with the Target off. The yellow streak is the edge of the Pick-off Mirror Support Arm. The next two surfaces, almost the same color as the Stop are the Pick-off Mirror itself, changed to red in images "8 -14."
Question: Is the corner of the carrier the same as the corner of the detector? It is the same corner that is used for the defining field rays that are in the AutoCAD drawing.