A while back I bought an adapter for my GoPro Hero 4 to use with my spotting scope. Well, technology moves on, but the company that I bought the adapter from didn't. They never made an adapter for the Hero 5. I even recently bought a mount for my iPhone 7 from them, so it's not like they're just sitting around, happy with what they have. They just haven't done one for the Hero 5. Well, I solved that problem.
I'm not going to mention the company by name. If you have this mount, then you'll know exactly who it is as I haven't seen any other mounts like this. I have included a 41mm optic adapter because I have a different spotting scope that I also want to use this with.
As usual, I've included the Fusion 360 file, so if you want to make your own optic adapter, all you need to do is edit the very first sketch and change the diameter of the center circle to the diameter you need.
I've also added two different versions of the GoPro mount, one that needs supports and one that doesn't. I didn't like the look of the supported model, so I designed one that didn't need supports, but it still works fine.