The COSMOS field has been a major target for astronomers because it has already been studied by many space and ground-based observatories. During the full LSST survey, Rubin will repeatedly observe the same regions of the sky, creating a dynamic record of cosmic activity that includes moving objects, changing stars, and distant explosive events. This COSMOS field view, consisting of half a million galaxies, is composed of multiple images by the LSST camera combined together. A Testing Ground For Future LSST ScienceThe COSMOS field will play a major role as researchers prepare for the full operation of the LSST. “The COSMOS field is a very important one for LSST science,” adds Phil Marshall, Deputy Director of Rubin Observatory at SLAC.