The New Horizons instrument Ralph is a combined visible/near-IR multi-spectral imaging camera. In time delay integration (TDI) node, the CCD array has a field of view of 5.7 x 0.037 degrees, comprising 5000 pixels. The single pixel FOV is 20 microrads. The design goal is 0.5 km per pixel spatial resolution at closest approach to Pluto. The spectral range is 400 to 975 nm. The primary mirror has diameter 7.5 cm. For the design closest approach of 12500 km, will Ralph achieve the 0.5 km per pixel spatial resolution requirement? What limiting distance still meets the requirement?