Optical calibration of the ELT-M4: automated testing procedure and results on the prototype

Le résumé fourni par la source

In the ELT, the wavefront correction is demanded to a quaternary deformable mirror; the M4 will be the largest Deformable Mirror ever built, with 5000+ actuators controlling its optical surface 2.5m in diameter, segmented into 6 petals. Given its size, high actuators count and tight operational requirements, it is mandatory for the optical calibration procedure to implement a large degree of automation, from initial alignment to system monitoring and to final reporting. In this contribution, we summarize the procedure we developed for the LBT and VLT adaptive secondaries and fine-tuned for the segmented M4; the focus will be on the actors, interfaces, data flow, data tracking, segments management and automation. The procedure, tested on the M4 Demonstration prototype, includes Optical Test Tower alignment, preliminary segments shaping, noise evaluation, measurement of Influence Functions and flattening in closed loop, calibration of the M4 metrology and phasing.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.