Residuals for Nix, Hydra, Kerberos, and Styx astrometry obtained by New Horizons and reduced by Porter & Canup (2023). The X, Y coordinates are relative separations of the satellite and Pluto’s system barycenter on the tangent plane in R.A. and decl. direction. It is equivalent to ﹩{\rm{\Delta }}\alpha \cos (\delta )﹩ and Δδ. The residuals were scaled by the spacecraft distance from the Pluto system in order to have kilometers as a unit. The rms of the residuals are (19, 42) km, (21, 25) km, (34, 42) km, (31, 32) km for Nix, Hydra, Kerberos, and Styx respectively. In angular unites these correspond to (131, 130) mas, (106, 114) mas, (170, 193) mas, and (206, 235) mas. For LORRI 4 × 4 images, the pixel size corresponds to 4.″08 pix⁻¹.