Does anyone know of a manufacturer, have drawings, or know how to build a set of rotating tube rings. I have my 12" GS mounted on an EQ6 mount (pier mounted). The setup is great but I need an easy way to turn the OTA to access the focuser when doing eyeball sessions. When the setup is used for CCD imaging it is not a problem. Thanks
Maynard
I can't help with much detail but I can describe what my old scope had (15-20 years ago...). I had an F6 8" Newtonian on a Samson Eq mount. Bought it off an elderly gentleman from St Ives in Sydney. He built the scope himself. It had adjustable lever action quick releases on the tube rings, and the tube rings were lined with felt. One tube ring was adjusted tighter than the other, so that with the front ring loosened the tube would turn in the back ring, but not slide axially. It worked like a dream!
The way I am building my current ones is to have the scope held tight like normal then when I want to turn it I just slightly loosen the rings and turn on a felt lining. Much the same as Al described above. To stop the tube sliding 'axially' I will place one of my paint can lock rings around the OTA so it can't slide down.
I have seen a discussion on CN on this subject. The answer there was to get an extra set of rings and place them each side of the mount rings and lock them to the balance point. The actual mount rings had some washers inserted so they would not lock onto the tube but still hold it steady. It was then a simple matter of turning the tube as needed.
And if Mick cracks it he will be very popular, as this is the bane of most if not all newt owners.
I have rotating rings on the MN76, and semi-rotating on the 10" newt. Semi means that I have to loosen them off significantly, and twist the tube around, then tighten. The MN76 are similar, but easier.
For quick looks visually I tend to use both in the dob bases.
I queried Mick on the rings months ago, at the time he had a heavy workload and I haven't pursued it since, but he said it could be possible. With a few more people after them it might make it worthwhile for him.
The parallax rings was where I was heading previous to that.
Here's the 15 buck solution - Plastic capping strip from Bunnings and a compression spring or two to splay out the rings. Drill and pop rivet where needed!
This solution works beutifully and ***NOTE*** it only requires the retaining ring to be placed on the uphill side - gravity does the rest!
If you're worried about inballances when changing eyepieces then make up some lead shot counterweights to hang about the tube (should be a must for newts on a gem anyway)
Rotating tube rings
