I have a 152.4mm Dob. I can't use it, and I wouldn't want to. I perfer looking for objects the hard way(using my finder 'scope, which is actually a piece of CPVC). If you just tell a device where to put the 'scope, and PRESTO! its' there, that's nice and quite effortless. Now, if you look for an object for hours, then find it, instead of just seconds, it is a much nicer victory. Jonathan