Commissioning of the Vera C. Rubin Observatory

Abstract

The Vera C. Rubin Observatory began commissioning its camera, LSSTCam, in April 2025, with the Legacy Survey of Space and Time (LSST) scheduled to start in 2026. A primary science goal is constraining Dark Energy through weak gravitational lensing of the large-scale structure (cosmic shear). After a full year of data from LSST, these measurements are expected to reach precision comparable to recent Dark Energy Spectroscopic Instrument (DESI), providing an independent test of hints that Dark Energy may evolve over time. However, cosmic shear requires exquisite control of instrumental systematics. This proceeding presents an overview of the Rubin Observatory commissioning -- the successes achieved and the systematic issues we are working to resolve.