Euro50

The Euro50 is a telescope for optical and infrared wavelengths. It has an aspherical primary mirror with a size of 50 meters and 618 segments. The optical configuration is of Gregorian type and the secondary mirror is deformable for adaptive optics. Observations can take place in prime focus, Gregorian foci, and Nasmyth foci using additional relay mirrors. The telescope provides seeing limited observations, partial adaptive optics with ground layer correction, single conjugate adaptive optics and dual-conjugate adaptive optics. For prime focus observations, a clam-shell corrector with a doublet lens is used. The primary mirror segments can be polished using the precessions polishing technique. "Live Optics" denotes the joint segment alignment system, secondary mirror control system, adaptive optics and main axes servos. An overview is given of the live optics architecture, including feedback from wavefront sensors for natural and laser guide stars, and from primary mirror segment edge sensors. A straw man concept of the laser guide star system using sum-frequency YAG lasers is presented together with a solution to the laser guide star perspective elongation problem. The structural design involves a large steel structure and a tripod of carbon fiber reinforced polymer to support the secondary mirror. Integrated models have been set up to simulate telescope performance. Results show that an enclosure is needed to protect the telescope against wind during observations. The enclosure is a very large box-shaped steel structure.