Wobble is tilting of the rotation axis relative to an ideal vector (normal to the rotation plane). This can have a dramatic impact in terms of precision performance characteristics (especially at larger distance from axis of rotation). Taking the case described above (with points of interest, 200 mm away), even a minimal ± 50 µrad error can result in ±10 µm of runout error.
To minimize this type of runout error, air bearing rotary tables can be used. Air bearings offer improved guiding performances over mechanical bearing counterparts (essentially floating over precision reference surfaces). As one example, a PI A-634 Air Bearing Rotation Stage can achieve wobble performance of only ±1µrad, resulting in ±0.2µm of runout error (again at 200mm distance). High precision air bearing rotation stages are also clean, non-wearing, and maintenance free - which is especially important for high duty cycle operations with continuous spin operation.