... Primary mirror actuators . Secondary mirror actuators . ... Consequently, the resolution of the secondary mirror actuators must be fine enough to not contribute significant astrometric error. ... The resolution of the axial actuators for the primary mirror is set by the criterion that the tilt quantization error not produce significant decollimation. The quantization error of the primary actuators can be compensated by the finer tilt and lateral motions of the secondary actuators. ... mas . ...