The 35th annual conference on Astronomical Data Analysis Software & Systems 2025 in Görlitz, Germany

After 45 years in operation, and two decades of remote queued service observing (QSO), Canada France Hawaii Telescope is developing Kealahou: a reconstruction of our entire QSO software system.

Kealahou started as a platform for a single spectrograph, and has since grown to host CFHT’s main suite of instruments, a “Phase 1” proposal submission and review system, and science operations management tools. With these features, the complete QSO process, from proposal creation to data access, is now encompassed by a unified API and web application. Over the next few years, Kealahou will gain another capability which will bring CFHT to the forefront of time-domain astronomy: integration with the AEON network, alongside a ‘Rapid Target of Opportunity’ observing strategy.

Kealahou replaces our use of obsolete, proprietary database and web platforms with modern, open-source technologies. System logic has been extracted from the UI and database into an API-based application layer, providing new flexibility to create tools that interface with the system. The software is built and deployed through an automated pipeline. Crucially, Kealahou runs in parallel with CFHT’s legacy QSO applications and databases, through the use of custom database bridge code. This allows for continual incremental improvements, while supporting ongoing CFHT science operations.

Developing Kealahou to support legacy software and tools has proved to be both rewarding and challenging. Here we present the objectives, design, and technologies that underpin Kealahou, explore the future for the application, and discuss the pros and cons of incrementally developing a new system which retains the ability to interoperate with our legacy software.