[1 Stage]
Ratio : 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20

Backlash
 Ps : ≤ 2 arcmin
 P0 : ≤ 4 arcmin
 P1 : ≤ 6 arcmin
 P2 : ≤ 8 arcmin