|
It minimizes errors when making shifts in traverse (left and right).
The gunner / FDC doesn't have to "make the jump" at zero.
3300 mils minus 150 miles equals 3150 mils.
3125 mils plus 250 mils equals 3375 mils.
But if you used zero mils as your index line, then:
100 mils minus 150 mils equals 6350 mils.
and
6275 mils plus 325 mils equals 200 mils.
|