A scraper mirror reflects the beams to {TAIL ~ a thermal imager} which reflects the beams to {HEAD ~ a pair} of NaCl beamsplitters 
A scraper mirror reflects the beams to { TAIL ~ a thermal imager } which reflects the beams to { HEAD ~ a pair } of NaCl beamsplitters
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH