(a) Distortion pattern across the focal plane. The pixel scale is 0﹩\mathop{.}\limits^{\unicode{x02033}}﹩485 pixel⁻¹, and the distortion amplitude remains below 0.05%. (b) Astrometric accuracy for 1084 stars in NGC 6819, showing astrometry rms accuracy of 0﹩\mathop{.}\limits^{\unicode{x02033}}﹩06 in both R.A. and decl. relative to Gaia EDR3. (c) Lucky imaging PSF. A Moffat profile, with its shape parameter β converging at ∼1.5, yields an FWHM of 0﹩\mathop{.}\limits^{\unicode{x02033}}﹩5, providing a more robust characterization of the extended wings than a Gaussian fit. A logarithmic y-axis is used to emphasize the structure of the outer wings. (d) Encircled energy growth curve, with the EE80 radius of approximately 1″ (about 2 pixels).