Outer solar system has now been surveyed to a completeness limit of about 21 mag in the R band. This figure shows what size and distance an object would be for several different albedos for a 21st magnitude object. Shaded areas correspond to completeness limits for albedo <0.1 (light), albedo <0.25 (medium), and albedo <0.625 (dark). It is clear that a Pluto (1161 km) or even larger sized object could easily have gone undetected to date if beyond a few hundred.