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