LST-2 Camera Installation Marks Completion of the Four Large-Sized Telescopes

13 Jun 2026

Figure 1: LST-2 camera being transported to ORM before installation on the telescope. Credit: LST Collaboration

On 12 June 2026, the LST collaboration successfully completed the installation of the camera of the LST-2, one of the four Large-Sized Telescopes (LSTs) at the Roque de los Muchachos Observatory (ORM) on La Palma.

The installation of the camera is the final major assembly milestone for the telescope, marking the completion of the construction of the four LSTs. Following the successful installation of the cameras on LST-4 in 2025 and LST-3 earlier this year, LST-2 becomes the last of the three production telescopes to reach full mechanical completion.

The first telescope, LST-1, was inaugurated in 2018 and has since been used for commissioning activities and scientific observations. Construction of the remaining telescopes (LST-2, LST-3 and LST-4) has progressively advanced over the past years, culminating with this final camera installation.

Figure 2: The installation team after the successful installation of the LST-2 camera.

Each LST camera, weighing almost two tonnes and housing 1,855 ultra-fast photomultiplier pixels, is the heart of the telescope. Positioned 28 metres above the 400-square-metre mirror dish, it detects the brief flashes of Cherenkov light produced when very-high-energy gamma rays interact with Earth’s atmosphere.

The installation required a carefully coordinated lifting operation, during which the camera was hoisted by crane and mounted onto the telescope structure with millimetre precision before the connection of power, cooling and data acquisition systems.

The completion of LST-2 marks the end of the construction phase for the four Large-Sized Telescopes. With all four telescopes now structurally complete, the LSTs enter their final commissioning phase. The collaboration will now continue with commissioning activities and the gradual integration of the telescopes.