ADJUSTABLE COUNTER WEIGHTS




A common hurdle to to overcome with telescopes , in particular Dobsonian telescopes is balancing. The main culprit is the dreaded eyepiece. Most eyepieces are in the order of a few ounces, but some for example 2" Nagler's and Panoptics are weighed in pounds, in other words when you slide your 10mm plossil into your focuser your scope reaches for the heavens , but when you put in that heavy 2" it decides it wants to take a dirt nap. Well Ladies and Gents, I've come up with a solution for this. While chatting with my very good friend Darrel the other night our conversation came around to this very problem, which got my gears turning and out popped the solution...An adjustable counter weight. I'll take you through the steps to build one.


There is a fair amount of trial and error involved with this project so a fair bit of tinkering is involved ,but I feel it is well worth the effort . Find which one of your eyepieces in the middle weight range and slide it in your focuser . Cut a piece of 1/4" rod at approx 24" (the rod may need to be shortened or lengthened) and tape this onto your tube assembly. start with a weight of 1lb (you may need more , you may need less) and position it in the centre of the rod , now balance your scope and mark the position on the rod. Slide in your lightest eyepiece and move the weight until it balances , do the same with your heaviest eyepiece. If you can't get it to balance try a longer rod or more weight. When you have located the end limits of balancing mark the rod and cut it . You should leave an extra couple inches on either end , you never know you might inherit a heavier or lighter eyepiece. At this point you know the rough parameters of your adjustable counter weight.



Buy yourself a nice chunk of round stock , 1" - 1 1/2" in diameter calculate how much you will need to match your temporary weight . Drill a 1/4" hole through the centre , drill a 1/4" hole through the side until it meets the other hole. Tap out the hole in the side at 5/16 NC. Slide the 1/4" rod through the 1/4" hole. Drop a 1/4" ball bearing into the hole threaded with the 5/16 threads followed by a short spring and an allan head machine set screw (this is to adjust the ball bearings pressure against the 1/4" rod . Mount the whole assembly on the telescope. Go through the eyepiece balancing procedure again and accurately mark the positions. Remove the assembly and score the balance positions on the 1/4" rod with a file , these groves will enable the spring loaded ball bearing to catch and hold position yet still be able to slide to another position when enough force is applied.





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