FWIW, since I completed the scope in 1988 I've never needed to move the tube in the rings. In fact, when we opened the rings last fall it was the first time they'd been opened since '88. So I'm really not concerned about pinning it in place. If someone does come up with some sort of heavy piece of something to hang on the back we can just do a combination of putting temporary weights in the front and sliding the existing weight further down the declination shaft. patrick On 16 Mar 2011, at 07:46, Chuck Hards wrote:
Why use tube rings and then disable them with a pin? Suddenly you have lost the ability to quickly achieve longitudinal balance if using heavier or lighter than usual accessories. Admittedly, at SPOC we don't really have many (if any) members using the telescopes with any significantly massive instrumentation attached, but the option is nice. With the tube pinned, clamp rings become simply dead weight. May as well just screw the OTA to a saddle and sell the rings.
Properly shimmed (felt) rings cannot be "overtightened" anyway. A set of tube rings is too far away from the lens cell on a long refractor to introduce any unwanted stress to the cell.