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Balance that was so far off on my 8" Orion Dob which caused my father and I to use 15lbs. of counterweight was of utmost concern. We had added so much to the front end (larger secondary, 4-vane spider, 2" Crayford Focuser) and had removed so much from the rear (replaced the heavy partical board Orion cell with a cast aluminum cell) that the scope was totally out of balance. At one time, I used the largest rock that I could find as counterweight during a star party since I had forgotten my weights at home (pictured at right). I vowed never again to use a scope that required so much offset of weight.
To ensure that counterweights would never have to be used on my new scope, we went two routes that 'sealed the deal.' First off, we increased bearing size from 4" (standard Orion 'mystery plastic' bearings) to 8.5" diameter ABS tubing. The larger diameter of the bearings give the scope a better feel in the altitude axis and also increases friction. With the ABS tubing riding on two cubes of virgin teflon, the scope moves with a single finger and stays where you point it.
However, one cannot be too sure a single defense to a problem will work; so we made an innovation that at the time of construction was virtually unheard of. We built a cradle around our tube and sliced it into two parts with two latches on top and two hinges on the bottom. This would allow the cradle to snap and unsnap around the tube so the user can slide the tube forward or backward, changing the balance point according to weight.
With this new thinking and innovation in place, the scope climbed yet another notch of excellence. The bearings not only make the scope more attractive than smaller diameter ones, but also perform superb in the field. The tube cradle is also an undespensible addition that adds greatly to the scope's performance.
