The Roque de los Muchachos Observatory (ORM) of the Instituto de Astrofísica de Canarias (IAC), located on La Palma, has reached another important milestone with the installation of the camera of the LST-4, one of the four Large-Sized Telescopes (LST), which will be part of the Cherenkov Telescope Array Observatory (CTAO), currently under construction. The installation of the camera represents the completion of the telescope assembly and marks its transition to the commissioning phase.

After a thorough performance evaluation at the IACTEC building, the IAC's technological and business cooperation space in La Laguna (Tenerife), the camera was shipped to La Palma on 13 May, where it was installed on the LST-4 Cherenkov telescope on 22 May, following a complex and carefully coordinated procedure. After extensive preparation and alignment work, the almost two-tonne camera was lifted by crane and attached to the telescope structure with millimetre precision. The process involved teams from several national and international institutions working synchronously to ensure safety and protect the delicate instrumentation.

‘The IAC has made available to the project the advanced technological facilities of IACTEC, where critical evaluations of the components are carried out. We also fully manage the tendering processes and supervise the contracted services, while IACTEC carries out exhaustive validation tests on each camera before it is sent to the Roque de los Muchachos Observatory,’ explains Ramón García López, Principal Investigator of the CTAO group at the IAC. ‘This quality control work is essential to ensure that each component meets the strict scientific and technical requirements of the CTAO project, thus guaranteeing the success of operations at the Observatory,’ he says.

Thousands of eyes to capture cosmic flashes

The LST-4 camera has a wide field of view of 4.3 degrees and consists of 1,855 photomultiplier tubes (PMTs). These highly sensitive light detectors convert faint flashes of Cherenkov light - emitted when high-energy gamma rays interact with the Earth's atmosphere - into digital signals for scientific analysis. Each PMT is paired with a specially designed light guide that improves efficiency by directing photons towards the detector.

The camera's internal electronics perform real-time signal analysis using advanced algorithms to identify the characteristic fingerprints of gamma-ray events. To capture the fleeting Cherenkov flashes associated with them, which last only a few nanoseconds or billionths of a second, the camera rapidly digitises and records the signals at gigahertz (GHz) sampling rates, processing up to a billion data points per second, by a factor of thousands or millions of times faster.

More state-of-the-art telescopes for the Canarian sky

With the camera now installed, the LST-4 enters its commissioning phase, joining the LST-1, the prototype and first telescope built at the CTAO-North observatory site. During commissioning, the telescope will undergo rigorous testing to verify that it meets the scientific and technical requirements of the project. In parallel, the LST Collaboration, in which the IAC plays a leading role, will continue the construction of the two remaining LSTs at the ORM.

This achievement is evidence of the continued growth of the Canary Islands Observatories and the IAC's unceasing scientific and technological activity, consolidating its position as a world-leading centre. The successful construction of the LSTs on La Palma reaffirms the role of the archipelago as a pole of attraction for top-level international projects, which find in the exceptional quality of the Canary Islands sky and the professionalism of its technical and scientific staff the ideal conditions for the development of the astronomy of the future. With each new milestone, the IAC and the Canary Islands Observatories reinforce their position as a world reference in astronomical research and cutting-edge technological development.

Contact at the IAC:
Ramón García López, ramon.garcia.lopez [at] iac.es (ramon[dot]garcia[dot]lopez[at]iac[dot]es)