The beam splitter 30 may split the image beam {HEAD ~ C} into {TAIL ~ a first projecting beam} C1 and a second projecting beam C2 
into
The beam splitter 30 may split the image beam { HEAD ~ C } into { TAIL ~ a first projecting beam } C1 and a second projecting beam C2
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH