IOMAC2027 Industrial Keynotes
Industrial Keynote 1
Structural Vibration Monitoring of an Extremely Large Telescope
Babak Sedghi, European Southern Observatory
Babak Sedghi holds a doctorate in control engineering and has worked on the control design and dynamical aspects of the European Southern Observatory’s Extremely Large Telescope (ELT) since 2004. He currently leads the vibration management activities for the telescope, spanning modeling, error budgeting, and requirement specification through to system-level performance verification and the permanent vibration monitoring system now being deployed at the ELT site in Chile.
ESO’s Extremely Large Telescope (ELT) must resolve nanometer-scale motions across a 5000-ton, alt-azimuth structure supporting a 39-meter segmented primary mirror. Achieving diffraction-limited performance means controlling vibration (from wind, drives, cryocoolers, pumps, and seismic background) at every level of the observatory. A system-level vibration budget, built from measured and modeled source data fed into a combined structural/optical model, has guided the design and verification process so far, but permanent structural monitoring is fundamental to confirming how the as-built telescope behaves once assembled on site.
This talk presents ESO’s plan for closing that gap: a permanent structural vibration monitoring system whose purpose extends well beyond operational modal analysis. Continuous monitoring lets engineers track how conditions and structural behavior evolve over time, distinguish and localize contributors to motion at the mirrors and hosted units, estimate the resulting wavefront error, and trace it back to specific sources, enabling proactive mitigation and, eventually, predictive maintenance, rather than relying on one-off measurement campaigns.
The system is built around low-noise, tri-axial MEMS accelerometers from Dewesoft, networked over EtherCAT with sub-10-microsecond synchronization, chosen for their very low noise floor, wide dynamic range, and ease of scalable deployment across a structure spanning ten of meters. A phased rollout begins with the dome and telescope pier and later extends to the mirror units as they are integrated, allowing monitoring to start well before formal telescope acceptance. The first phase, installed on site in Chile in December 2025, is already operational and has captured wind-driven response and seismic events, confirming design assumptions and offering an early view of the real structure’s dynamic behavior.
Industrial Keynote 2
To be announced.
