An extremely stable motorized mount for initial alignment of two dichroic beam splitters in the instrument was required. The mirrors reflect visible light and transmit the NIR are located close to the pupil plane are very sensitive to tilt and flexure errors which could be introduced to the wave-front sensor.
The technical specifications to be met in a very tight operating envelope were as follows:
- Tip / tilt range around the major axis of the elliptical mirror: ±2
- Angular resolution <0.5 arcsec
- Angular position repeatability <1 arcsec
- Static position stability (elevation 0° to 90°) <20 arc seconds
- Minimum resonant frequency >110Hz
PI found a solution based on its compact, high stability PiezoWalk linear motor – a tried and proven technology used on many semiconductor and high-energy physics applications in the past.