Stubbs was the inaugural project scientist for the Vera C. Rubin Observatory/LSST and works on precision photometric calibration (e.g. tunable collimated beam projectors) for its 3200-megapixel wide-field survey camera, alongside dark-matter/dark-energy searches and tests of gravitation. Included as a borderline, not-preferred astronomy-instrumentation case: the camera/calibration technology is complex and cutting-edge but is CCD-based rather than a quantum sensor per se.