Solving Two-Axis Balance Problem Without Counterweights
The FTX solves the two-axis balance problem by providing a saddle that can be adjusted up and down.  This allows setting a position in which the weight of the OTA counteracts the off-axis moment caused by the star diagonal, eyepiece, finder scope, and any other component that lies off the centrerline of the OTA.  By adjusting the saddle position up or down and the OTA position fore or aft in the saddle, the center-of-mass of the entire rotating assembly can be placed on the centerline of the altitude axis.  With this one-time adjustment, the scope can be rotated without producing any awkward balance shifts.