[Tinderboxsky (Steve)]

The very effective flexible slow motion controls for my mount inspired me to think about applying these principles to eliminating some manual focusing vibrations at high magnifications. No matter how careful, even when using the 7:1 reduction on a buttery smooth focuser, I was finding it impossible to avoid some momentary vibrations that made it a slow process to find the exact focus point at higher magnifications. I was looking for a non-powered solution to improve my visual observing experience.

So, my solution is a flexible slow motion control for the focuser knob. It consists of a simple clasp that slips over the fine focus knob, a section of marine grade shock cord and a left over lightweight plastic knob. The clasp is fashioned out of left over PVC pipe, some wood and sections of plastic tubing. A rubber band gives the clasp sufficient holding power to stay on the focusing knob during the observing session whilst still allowing the clasp to be easily slipped on and off the focuser knob. It took some experimentation with different sizes and lengths of shock cord to get a balance between flexibility to avoid transmitting vibrations and sufficient torque to enable to smooth turning of the focuser knob. 8 mm cord seems to be the best fit.

The flexible slow motion control has completely eliminated all vibration when focusing, even at the highest magnifications. Having a completely still object just makes it so much easier to find proper focus. It is easy to slide on and off and sits quite comfortably on the telescope all night.

Cheers

Steve