Rotating Rings

[Kev11]

I believe I have thoroughly searched the IIS forum and links from posts.
The commercial rings are elegant but would be a massive over-capitalisation of my gear. Some of them seem to be no longer available anyhow.
I am thinking of trying the fixed-ring on tube idea i.e. to stop loss of scope while the mount rings are slacked off for rotation. The only possible problem I forsee is that the felt on the mount rings (Skywatcher gear) is particularly tenacious - I have had to open the rings right up at times to release from the tube. So the first question:
Is there any adhesive tape that might be more "slippier" but still secure when the rings are tightened?
The more general question: has anyone come up with another inexpensive DIY solution for the Newtonian rotation problem?
Cheers

[jjz]

You could try something like this:


http://www.leevalley.com/US/wood/page.aspx?p=32182&cat=1,110,43466,32182


If you do please posts your results, been thinking about doing something similar.....

JJZ

[OzEclipse]

That tape looks like good stuff. The old fashioned solution would be wood on wood finely sanded and finished in danish wax.

I built a 6 inch newt scope in the 1970's with the ATM club of Qld. The club cast all its own aluminium parts and machined them. Glass blanks and aluminium ingots went in to the foundary and finished telescopes came out the other end. My good friend and mentor the late Cliff Duncan was the powerhouse and engine room of the club. Can't praise him highly enough although if they have internet wherever he is now, he'd be reading this and saying something that I can't post here. Rotation rings Al on Al were standard equipment on all scopes.

I did a LOT of visual observing with that scope during the 1980's. I have to say, good rotation rings are the bees knees for visual work on an EQ mount. You don't even need to slacken the cradle tension strap on mine. You just find the right tension, dry lube on the bearing surfaces and leave them like that. The tube spins easily with minor force and stays where you leave it. The rings are nearly concentric to the optical axis so you don't even lose the image field when you rotate with anything longer than a 10mm eyepiece. Can't recommend them highly enough for visual work. You'd need to be careful of flex and movement for photography although most photographers using newts point the focusser parallel to the dec axis - Joe

[raymo]

A super cheap D.I.Y. alternative to rotating rings is as seen on my scope.
Steel or aluminium strip 25 or 30mm x 3mm. Attached as shown in pic to
existing threads in top of rings. Bent at 90 degrees at the end. The two
mounting holes are slotted in case of need to move the OTA backwards or forwards for balance purposes. A small piece of Teflon is stuck to the
inside face of the 90 degree bend to make turning the OTA smooth.
I leave the rings slackened off enough for me to be able to turn the tube
easily, and just nip them up when starting an imaging run.
Incidentally, it makes a convenient carrying handle.
raymo

[Kev11]

Thanks for the info, guys.
Joe, I will pursue that tape.
Joe Cali: Yes, the good old days when those who were going to use the gear made it. Unfortunately, I was a poor uni student in the 1960s, ground a 6" mirror but couldn't afford the aluminising or even an ortho eyepiece! Surely, the 'scope manufacturers should be considering rotating rings as one of the next marketing ploys.
Raymo: That looks like a very simple solution, will look into it.

[inertia8]

I've seen a guide to using two sets of normal rings modified to allow them to slide against each other. The rings connected to the dovetail are slackened slightly to allow rotation and the other pair hold the scope in position against them.

Raymo's option looks cleaner and would be a lot cheaper though

[peter_4059]

Something I've tried on my 10" newt was the Wilcox solution:

http://www.andysshotglass.com/wilcox_rotating_rings.html

I got some large stainless steel hose clamps and some clear plastic tubing. I had to join 2 hose clamps together to get a large enough diameter to fit around the scope. You slide the hose clamp through the tubing then wrap it around the scope and re-connect the ends of the hose clamp. I got all the parts from Bunnings.

http://www.bunnings.com.au/kinetic-130-152mm-304-stainless-steel-hose-clamps_p4920201

Parallax make rotating rings however these cost quite a lot and are very heavy.

http://www.parallaxinstruments.com/rings.html

[MattT]

Here is my idea for my 10" Newt.

It has Parallax rings already which are solid aluminium. I add another ring, ATM naturally, made up of 6mm aluminium with ply inbetween for depth and add wheels that are meant for sliding mirrors on wardrobes. The new ring needs to be bolted or clamped to the tube. A type of Wilcox ring but more involved.

One ring at the focuser end would do it I think? Won't know til I build it.

Raymo's idea looks good too, might do a combo of the two.

Matt