Purtroppo, questa descrizione non è stato tradotto in italiano, in modo da trovare a questo punto una descrizione inglese.
The rack and pinion gear drive:
A conventional Crayford focuser works with contact pressure. The weaker the pressure, the smoother the focuser, but there is always the risk of slipping, because adjustment and bearing are combined. This focuser is completely different:
The draw tube is fixed in place by ball bearings. The bearings are optimized to provide maximum stiffness. The adjustment of the extension tube is achieved by a helical toothed rack. The advantage is an absolutely jerk-free adjustment.
The clamping of the focuser position is also optimized. No clamping screw simply presses on the draw tube, but the position of the adjustment is fixed. Thus, the focus position is held 100%.
