Two-Axis Balancing Is Key Easy Rotation

Two-axis balancing is the key to light, responsive motions that make observing pleasant and intuitive.  The Nova Hitch integrates two-axis balancing into the core design without the use of counterweights.  Instead, it uses the weight of the telescope itself to counterbalance the off-axis loads created by the star diagonal, eyepiece, finder, bino-viewer and other accessories by shifting the telescope attachment point up-and-down as well as fore-and-aft.  Together, these adjustments allow the mass of the telescope, accessories, and saddle to be centered on the altitude axis so that the scope is stable when pointed to any elevation.

Without two-axis balancing, a scope may not stay pointed without being forced to hold position.  The problem occurs with most alt-az mounts because the center-of-gravity of the scope lies above the altitude axis even when the scope is balanced end-to-end.  To appreciate the resulting instability, imagine standing up in a canoe.

 

No-Tool, On-the-Fly Adjustable, Two-Axis Balancing

 

The Nova Hitch provides integrated facilities to easily address all manner of balance situations rather than leaving users to struggle with out-of-balance loads.  Ignorance of balance is not bliss!

 

Minor variations in balance are easily handled by the clutches.  Clamping and unclamping the axes to point the telescope is NOT needed.

 

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 five reasons.  Here's the physics:

  • 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.

  • The effect of an imbalanced load will change as you rotate your scope up and down in altitude — making the feel of the movements variable and hard to become accustomed to.

  • If you try to balance the feel between the axes by stiffening the movement in azimuth, then you will be confounded not only by the variable feel in the altitude axis but also by the changing effective lever arm for the azimuth axis as the scope is raised and lowered in altitude.

  • High levels of friction mean more force is required to start the axis turning.  Not only is this large force hard to judge, but the laws of physics demand that the starting force will be at least a little greater than the force required to maintain the turning motion.  A jerking effect is inevitable.  When trying to make the small movements required for tracking and centering objects, this jerking effect is quite significant — especially when magnified many times by a telescope.  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 which the axis has in one direction versus the other.

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

No amount of apparent "smoothness" during longer sweeps can overcome the jerking effects for small centering and tracking adjustments.  A mount which resists shifts in balance is a mount that resists turning!  That’s the physics.  Hitch mounts eliminate these problems by making complete, adjustable two-axis balancing easy — and by employing true low-friction bearings to make turning forces predictable, intuitive, and controllable.

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