Astrometric validation against JPL Horizons for five main-belt asteroids: 417988 (2007 TW274), 436248 (2010 BW65), 284091 (2005 ME4), 411380 (2010 VH63), and (2021 MQ23). Left: sky track of the group difference detections relative to the first epoch, with the Horizons ephemeris overplotted. Arrows indicate the direction of on-sky motion. Objects are distinguished by color. Right: observed-minus-computed (O − C) residuals, with the same color encoding. Small circles show the O − C residual at each individual epoch. but are too small to be clearly visible due to low astrometric scatter. Stars mark the per-object mean O − C. The cross on each mean point shows the 3σ uncertainty on the mean, and the ellipse shows the 3σ positional uncertainty of the Horizons ephemeris at the mean epoch. The per-epoch residuals are not independent, as measurements of a given object may share common astrometric systematics that do not average down with the number of epochs. Timing uncertainties are expected to contribute negligibly at the apparent rates of the asteroids given the ∼0.1 s timing precision achieved with NIRCam rolling shutter timing corrections. All four objects show O – C residuals consistent with their predicted position from Horizons.