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