Thanks nabe, What we need is all in your picture.
Letfs see what happen if the reticule is fixed on the sight glass.
If the pilot's eye is placed at 18 inches far from the gun sight, and if the range to the target is 500feet (6000 inches),
6000/18 = 333.33
This mean slide movement of the pilotfs eye will appear as an error of 333.33 times.
If you shift your face just two inches to the left, bullets will go through 666.66 inches (55.55feet) left of the target.
No fighter pilot wants to use this kind of gun sight.
Real gun sight is here.
http://www8.big.or.jp/~wbalive/misc/ah/t34gs.htm [This message has been edited by meza (edited 10-08-1999).]
[This message has been edited by meza (edited 10-10-1999).]
[This message has been edited by meza (edited 10-13-1999).]