First light: 23 November, 2004.
Designed and built by: INAF — Osservatorio Astrofisico di Arcetri, Italy.
Description: Phasing the segmented primary mirror of an ELT is a key work requiring phasing (differential piston correction) and alignment (tip-tilt correction). The pyramid co-phasing wavefront sensor is a prototype that is able to do phasing and alignment of the 72 mirror segments of NAOMI at the same time.
Publications: research or technical papers, etc.
S. Esposito, E. Pinna, A. Tozzi, A. Puglisi and P. Stefanini, 2005, "Pyramid Wavefront Sensor at the William Herschel Telescope: Towards Extremely Large Telescopes", ING Newsl., 10, 17