Telescope Reviews: Attention Orion EON owners please

We have an EON 120 which will be the Grand Prize at our next Deep South Regional StarGaze. In checking it out I found that while I had no trouble loosening the "chrome ring", it was awfully noisy due to the threads within being metal on metal. A very grating noise sure to be disturbing at star parties. The metal on metal attachment almost assures that use can create some galling between these opposing parts resulting in stuck parts such as what you see. Yours was likely overtightened when built so you have to take extra steps to break the bond and then make fixes to assure that it does not happen again As a fix I totally detached the focuser including the chrome ring and then lightly lubricated the offending threads (male side on the black anodized interface which remains on the telescope tube and female threads on the inside of the chrome ring)with Sil-Glyde, which is a lubricating compound made by AGS. It has a very wide temperature working range (-20 to +400 F). It is a silicone based product and I have used it for all manner of telescope related products. It is harmless to rubber. I have never had a problem with it.

To get the focuser off, and you do have to loosen the chrome ring to do that, the key is to apply even and steady pressure. It seems you have already tried this. To get even and steady pressure on the tube and focuser I would suggest that this should be a two man operation. So far if it is just you it is very hard to have pressure evenly applied around the circumference of the scope on the rings. Get a second person holding the tube steady with his or her hands around the tube. Using both of your hands and steady pressure, try to loosen the focuser (do not put pressure on the pinion shaft as you may damage that). Unscrew counter-clockwise, as viewed from the rear. If that does not work, try again after applying heat to the chrome ring, via a hair dryer. This should work.

The rotating focuser on the EON basically works the same way as does the focusing adjustment on many finder scopes - i.e. - threaded ring goes onto the threaded front end of a finder tube followed by a threaded cell holding the objective. When the two are brought together, they lock together at that point and uneven pressure prevents turning of both together on the threads.

Another possible way to skin the cat: You will notice a recessed allen screw on the focuser, bottom side, very near the chrome ring. If you loosen this the focuser (black part) will not "fall off". What this screw does is it fixes an internal tube with what looks like a pressure plate in place. As viewed from the front this part has two spanner holes and it can be loosened with an appropriate tool. However if the problem is this plate jammed against the chrome ring or the part the chrome ring screws on to, loosening the allen screw should allow you to unscrew the focuser pressure plate by turning the focuser body counter-clockwise. That could relieve some pressure between the chrome ring and interface part on the telescope tube, allowing you to unscrew that part too.

I would apply Sil-Glyde (or something equivalent) to the threads. It will give everything a nice hydraulic feel, prevent galling and jamming such as what you are seeing, and make focuser rotation noiseless.

Best of luck!

Barry Simon