{TAIL ~ Each composite illumination beam} is directed to be incident upon a separate predetermined location on {HEAD ~ the subreflector} which directs the illumination beams towards the main reflector 
{ TAIL ~ Each composite illumination beam } is directed to be incident upon a separate predetermined location on { HEAD ~ the subreflector } which directs the illumination beams towards the main reflector
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH