In addition to light from {HEAD ~ the light source} 74, {TAIL ~ the imaging optics} 78 also receive a locator beam 90 from an infrared light source 92 carried by a common substrate 85 with the light source 74 
In addition to light from { HEAD ~ the light source } 74 , { TAIL ~ the imaging optics } 78 also receive a locator beam 90 from an infrared light source 92 carried by a common substrate 85 with the light source 74
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH