The plane of reflectors 73 and 75 then makes with {HEAD ~ the horizontal an angle α/2} equal to {TAIL ~ half the maximum solar altitude angle} 
equal to
The plane of reflectors 73 and 75 then makes with { HEAD ~ the horizontal an angle α/2 } equal to { TAIL ~ half the maximum solar altitude angle }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL