ELT Active Phasing Experiment

The construction of the ELT is only possible with a segmented primary mirror. Scientists at ESO have developed a test bench called Active Phasing Experiment to study a new phasing technology and a new telescope control system. The key subsystem of this experiment is a scaled down Active Segmented Mirror (ASM) composed of sixty-one hexagonal segments of seventeen millimeters side to side (approximately 100 times smaller than of an ELT segment). Each hexagonal mirror can be controlled in piston, tip and tilt. Mar2007