Adapting the 23m LST-North mechanical structure design for the strong Chile seismic environment

The 23-meter Large-Sized Telescope (LST) is the largest of the Cherenkov Telescope Array's telescopes. Its first unit, LST-1, installed at La Palma's Roque de los Muchachos Observatory (2,250 m) in 2018, has been operating since 2019 with an ultra-lightweight 110-ton structure that repositions 180° in 18 seconds and is engineered for winds up to 200 km/h. To use the same design at the CTA Southern Observatory in Chile, the structure must meet significantly higher seismic demands.

MPP (Max Planck Institute for Physics) proposes integrating a seismic isolation system with the proven LST-1 design. This reduces seismic loads and dynamic amplification, avoiding extensive structural modifications and allowing the telescope design to transfer to Chile with only minor adaptations. The contribution presents the seismic isolation concept and its feasibility studies; MPP validated the concept through detailed finite-element analyses and long-term structural lifetime assessments.