3I/ATLAS · MOSFIRE
11 July 2025

Keck/MOSFIRE Y, J, H, and Ks imaging of 3I/ATLAS on 2025 July 11 UTC. Each panel spans 20 arcsec, north up and east left; scale bars mark 5 arcsec. Y combines 13 accepted native exposures in a throughput-normalized, exposure-weighted mean, retaining pixels supported by at least three exposures. J, H, and Ks use accepted field-subtracted stacks. Cyan Anti-Sun arrows point away from the Sun; white +v_hel arrows show the projected heliocentric velocity in the direction of motion, evaluated per filter with JPL Horizons. Arrow lengths are illustrative. No additional smoothing or pixel filling was applied. Independent stretches and colors are illustrative; apparent panel brightness is not photometry. Native data and aperture photometry are unchanged.