So I have had my spotter for a couple years now and took photo's with my iphone, but for Christmas my wife bought me a Sony RX100 3. Took it out and just held the camera up to the spotter, worked well.
Camera is a Sony RX100 III, spotting scope is a Meopta S2 HD w/ 30-60 WA lens. The diy mount is just a 2" threaded PVC collar with a 2" threaded piece screwed into it. I put a small piece of foam weather stripping in the collar that covers the threads. The camera then fits snug into the collar. The regular 2" pvc slides right over the eye piece. Works perfectly.