reference, the line of bolt holes that the 2 inch lens is on (
measureing from inner edge of enclosure:  bottom periscope mirror 170mm, 2 inch lens 223 mm, 
rail for nanoscan 61cm marking 493mm from inner edge of enclosure
numbers on rail are going down as we move away from periscope.  

position on rail, A1(h), A2(v) 13.5% width
58cm:  5477.42, 	5425.02
50cm:	4651, 		4645
45:	3850		3992
40:	3228		3321
34.9:	2499		2571
30:	1794		1857
25:	1076		1141
20:		saturated