The Griffin is a mythological animal with a head of a eagle and the body of a lion. In this case, the body is an LX200 Alt/Az Fork Mount and the head is an interchangeable OTA of any size from a small refractor to a Celestron 11" SCT.

This project was originally conceived as a way to use various OTAs on a single LX200 mount. The value of this concept is twofold. First is the ability to use the best OTA for a particular task. The second is to reduce the weight of the single largest component of the system. It is much easier to transport an OTA and fork mount separately.

The first model was a single arm version that was limited to small OTAs. It worked well but on anything larger than my 6" Intes Mak-Cas it was prone to vibration that took forever to damp. Rather than spend any time or effort finding ways to reduce the vibration issue, I scrapped the single arm approach.

To ensure that I could use all my OTAs, I went back to a dual arm fork mount. I used a mount from a 12" LX200. The distance between the trunnions is just enough for a Celestron 11" OTA to be easily inserted and removed. I built a crossbar that joins the two trunnions using an extruded aluminum bar. This is attached with aluminum angle brackets. At the center of the crossbar I have mounted a Losmandy G11 saddle which accepts standard G11 dovetails.

The only additional hardware required to make this setup work is a Z-axis counterweight. I have used the Losmandy WS C11/M10 system for this. The X-Y balance is accomplished by sliding the OTA forward or aft in the saddle. Once this is done you center the Z-axis counterweight at the pivot point and rotate the OTA to point vertically. Then by spinning the weight in/out you can balance the Z axis. This is actually faster to do and more accurate then balancing a standard fork mount set up. This is because you don't have to guess the right location to set the weight on the dovetail.

A big benefit to this setup is that the more gear you hang on the back of the OTA, the more "swing through"clearance you get between the fork arms as the OTA slides forward to balance properly. This becomes especially important when using CCD gear or the Intes 2" eyepiece turret.