Our observatories were in nominal operation during the full year, a novelty since the start of the pandemic. In Paranal, ERIS started operations in April and is taking amazing data, despite of some technical issues that are still being worked on. Other than the unexpected issue with the UT4 M2 deformable mirror, which is still being investigated, technical issues were well under control and science time availability was large. The M1 and M3 of UT1, UT2 and UT3 have now been re-coated and interventions in their infrastructure in preparation for the GRAVITY+ lasers have been successfully concluded. MOONS and 4 MOST are the next instruments to come, followed by FORSup, CUBES, GRAVITY+ and MAVIS. We expect to start the Phase A of BlueMUSE as soon as all interventions on ERIS are finished.

ALMA recovered from the cyber-attack at the JAO and closed Cycle 9 with a remarkably high number of hours, which indicates that 4000 hours per cycle are achievable. Cycle 10 is underway and will see the first dual time allocation observations with other facilities. Band 2, under ESO leadership, passed its pre-production review and is progressing towards the full manufacturing. The procurement of the new ALMA correlator (TALON), as part of the Wide-band Sensitivity Upgrade (WSU) is progressing, while the WSU Project charter was released. It is expected that the WSU project plan will be released, reviewed and submitted for ALMA Board approval in April 2025. ESO will discuss next year with the partners the contributions to the WSU as part of the ALMA Development programme. New faces in ALMA include the new Deputy Director for Operations (Norikazu Mizuno), the Deputy Director for Development (Alvaro González) and the new Head of the ESO ALMA Support Centre (Liz Humphreys).

ELT construction passed 50% completion, with remarkable milestones. Progress at the site has been moving at full throttle, with the civil work having been completed, the dome erected, and the first items of the telescope (azimuth tracks, warping harness, first floor of the Nasmyth platform) already in place. All this went in parallel to a financial crisis from the lead company of the DMS contract, which has been resolved. ESO could finally secure the change requests necessary to guarantee a performing telescope. Preliminary acceptance of the Dome and Main Structure is expected in July 2026. The first batch of (18) polished M1 segments is on its way to Chile, where the coating process has been designed, tested, and optimised. M2 polishing has reached a roughness of 64 nm rms, something never achieved before in a 4-m mirror. The 12 M4 mirror shells were delivered, while the M5 SiC mirror is making progress but remains challenging. The Phasing and Diagnostic Station (PDS), developed in house, successfully passed its Final Design Review, and the Pre-Focal Station (PFS) is being manufactured. All construction instruments (MICADO, MORFEO, HARMONI and METIS) are in various stages of Final Design Review. First technical light, delivering a fully commissioned telescope, is still compatible with May 2028.

Important internal ESO Programmes are also taking off, in particular a Quality and Information Systems (QIS) Programme and the Paranal Integrated Operations Programme (IOP). They are largely complementary, with the latter aiming at defining a new observatory operations model for the VLT/I and the ELT based on processes (rather than on activities), which is lean, remote and high-performance. A first critical element of the IOP is to prepare for the maintenance of the ELT Dome and Main Structure and the ELT Technical Facility in Paranal.

Community engagement remained in focus, with studentships, fellowships, internships, summer studentships, workshops and many other activities. Today (19 December 2023) I received the news from the ESO Library that also in 2023 more than 1000 refereed papers have been published, using data from ESO’s telescopes (or in the case of ALMA or APEX, on ESO’s shares of these telescopes).

All this puts ESO in a leading role in ground-based astronomy. ESO’s scientific community, with whom we work and which we serve, will have available the most advanced tools for astronomical observations in the foreseeable future. The prospective of many astronomical discoveries and breakthroughs remains higher than ever.

Let’s celebrate 2023 and look forward to an even yet more exciting 2024!

Xavier Barcons

ESO Director General