So way back when, (2007), Celestron was discounting the C4-R with black CG-4 mount to make way for the XLT 102. I purchased one for $249 shipped. Like many, I found the scope/mount combination prone to vibration, especially when focusing or even in a slight breeze. Having had a 120 F/8.3 Skywatchers on a CG-5 mount with the same aluminum legs, I chalked the vibrations up to the legs on the CG-4 mount and long moment arm of the
OTA. But I was unwilling to substitute the aluminum legs with either wood or steel due to the extra weight.
Last week, while setting the scope back in its storage location, I took hold of the OTA at the lens end and noticed that there was movement NOT at the legs, but at the base of the mount where the adjustment for latitude is made! I knew immediately that I needed a shim to remove the play at that location.
After removing the OTA, counterweight and shaft, I removed the mount from the latitude adjustment base. I found four thin, clear plastic "washers," two on each side. I needed something thin to take up the slight gap that remained. Fortunately, there was a thin piece of aluminum scrap on the floor, thin enough to be cut with an ordinary pair of scissors. I drilled a hole in a piece cut to match the plastic washers and inserted it between the two washers on one side of the mount. It was a BEAR getting everything aligned to get the bolt back through the hole to rebuild the mount, but I finally got the bolt to go, and got the whole scope and mount back together.
The result? NO source of wiggles from the newly-shimmed mount. Focusing is MUCH easier, with most of the vibration eliminated. And to think I went 12 years thinking it was the aluminum legs! Yes, replacing those legs would help even more, but had I replaced those legs first, I might not have noticed the real source of the greatest amount of vibration, and would still be frustrated with that vibration.
Roger
