Two-Axis Balancing Allows Holding Position Without Clamping

Without two-axis balancing, your scope may be balanced end-to-end when horizontal, but it will not stay where pointed in the sky without being forced to hold position.  Two-axis balancing is essential for fine, uniform telescope control.

The Half Hitch implements two-axis balancing without the use of counterweights.  To accomplish two-axis balancing without counterweights, one must be able to shift the telescope attachment point up-and-down as well as fore-and-aft.  A machined track on the Half Hitch's saddle plate provides the up-down adjustment, and the dovetail plate makes fore-aft adjustment easy.

Together, these adjustments allow the mass of the telescope and saddle to be centered on the altitude axis so that the scope is stable when pointed to any elevation and so that one does no work against gravity when turning the telescope.  This translates into the lightest and smoothest tracking and pointing.

Using modern (heavy) wide-field eyepieces or a bino-viewer makes two-axis balancing very important!

The adjustable saddle allows the payload to be completely balanced in two directions— up-down as well as fore-aft — yielding stable, torque-free positioning at all points in the sky.  More than simple slots, the saddle rides in a close-tolerance machined track that creates smooth adjustments and a rigid, unitized connection.


Why Adding Friction Doesn't Solve Balance

Some claim that if you add enough friction into the altitude axis of a mount, then you do not have to balance your telescope.  This is a bad idea for at least three reasons:

  • The unbalanced load will have to be lifted against gravity when turning in one direction and will be pushed by gravity when being turned in the opposite direction.  Turning the scope in one direction will necessarily feel much different than turning the scope in the opposite direction, making the scope hard to control.  Basic laws of physics guarantee this condition will exist for unbalanced loads.  Adding friction does not change this condition.

  • High levels of friction means more force is required to start the axis turning.  Not only is this large force hard to judge, the laws of physics demand that the starting force will be greater than the force required to maintain the turning motion.  A jerking effect is inevitable.  When trying to make small movements, this jerking affect is quite significant.  Frequently, in trying to compensate, one will let the turning force drop below the required level — and the jerking effect will get repeated.  Overshooting will be common, and one must reverse direction, which means one must also deal with the different feel that the axis has in one direction versus the other.

  • Overcoming the initial starting friction will invariably cause the structure to flex a little, storing energy that will cause a recoil when the mount is released.

No amount of "smoothness" can overcome these three effects — especially for small centering and tracking movements.  The Half Hitch eliminates these problems by making complete two-axis balancing easy and by employing true low-friction bearings to make turning forces predictable, intuitive, and controllable.

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