Has anyone successfully attached the OSMO to a telescope? I do have the gimbal extension and planning to mount the camera behind the telescope letting the gimbal free of any anchor point, since the motors would want to level the camera which needs to be fixed on the telescope sitting on its tripod. A secondary concern is how to get the telescope view in focus and as big as possible in the resulting pictures, since the OSMO's wideangle would require its lens to be quite close to the telescopes lens. Any advice appreciated, even if not personally verified.

I don't quite understand. Since telescope is mostly stationary. and Osmo is for shots in motion, maybe it's not the best companion?

OSMO has more useful features than a great gimbal. It has a good quality camera with no fisheye view and remote capabilities, including live streaming.
Anyway, the fact that I already have a spotting scope / telescope and the OSMO, I could make use of them to review and capture my archery target from a distance (70m)... all with a simple look at my phone.
The camera thread used to mount filters could be used to attach an adapter (custom if needed) which will help mount the OSMO camera at the back of the scope. The gimbal function is not needed and using the gimbal extension cable I can have the heavier OSMO handle mounted on the scope's tripod, even connected to an Inspire 1 battery through the battery extender. All I need to figure out is how to best mount them together such as the scope's projection is seen clearly and large enough on the OSMO's output.
I am not planning to purchase another camera with WiFi and streaming capabilities, so if the OSMO doesn't do the job then I will simply use instead a phone with custom software on it.
Thanks for any feedback.

Did you get anywhere with this?  I have the Action 4 and thinking alongside the same as you.  I might have the 3D print an adaptor