Gemini prime focus wavefront sensor

A Prime Focus Wavefront Sensor (PFWFS) has been designed and built at the Gemini Observatory. The system contains a Shack- Hartmann (SH) wavefront sensor and has been designed to use commercial components. The primary mirror of the 8 m Gemini Telescope has a complex active optics system that needs to be calculated during commissioning. The wavefront sensor was built to measure the image quality at prime focus, this eliminates the secondary mirror introducing supplementary aberrations. It has been successfully used during commissioning, to test the active optics.