Reflections on OpR4: A Successful Rehearsal for 4MOST Operations
by Lisa Kelsey on 2026-03-02
Operations Rehearsal 4 (OpR4) has now concluded, marking a major milestone towards routine survey operations. Designed as a full "dress rehearsal", OpR4 tested the entire operational ecosystem, from planning observations to processing data and feeding results back into future observing decisions.
A key goal of OpR4 was to finalise the data flow to demonstrate that 4MOST can operate as autonomously as possible on a nightly basis. During the rehearsal, teams verified that the observing system can automatically generate and schedule OBs, selecting targets and optimising their observations based on live observing conditions from the site.
Jakob Walcher (4MOST Operations Manager) says:
"For me the most impressive thing to see was the enthusiasm, competence, and hard work of everyone involved. We have been planning for this moment for the last decade - everyone was present and keen on making it work."
"I also sometimes felt a bit like a pioneer. For ESO, one of the foremost observatories on earth, a remote automatic scheduler is a new development. Being able to watch closely how 4MOST and ESO colleagues worked together to make this a reality was fascinating."
Members of the Cambridge Astronomical Survey Unit (CASU), who lead the data processing pipeline development for 4MOST, worked intensively throughout the rehearsal to ensure observations could be rapidly transformed into usable survey products.
Nic Walton and David Murphy, leading the 4MOST data management system (DMS) team, commented that the OpR4 exercise has successfully demonstrated the end-to-end functionality of the 4MOST processing system. This ensures that all data obtained from the telescope is transformed into science ready data products ready for the scientific community to work with. The OpR4 campaign was intense, but ultimately successful, and has meant that 4MOST could commence its full science performance verification (SPV) phase in advance of full survey operations. The 4MOST pipelines are now ready, let the science begin.
With OpR4 complete, 4MOST now moves into the Science Program Verification phase, getting ever closer to routine survey operations. We thank everyone across the collaboration who contributed to this intensive and successful rehearsal.