When using SkySafari 6 Pro (on a MacBook Pro running MacOS X 10.11.6), in some cases faint stars are shown twice (but at slightly different positions, a few arc-seconds), once with the TYCHO designation and once with the GAIA designation. This is very confusing since these are spurious double stars, not real double stars. Is there a way to disable one of these catalogs ? In SkySafari 5 Pro the stars are shown correctly. I did purchase the UCAC5 Extension database, which might be related to this problem.