I've been using a "Phone Cam" and like it a lot. It's basically like a chuck that clamps down on your scope or binos or whatever you want (fits a range of optics as a result) and the other end of it threads into an adapter that you glue on your phone. So I unthread it when I'm done and put the large piece in a protective case, only the thin adapter stays on my phone. I did have to modify my phone case to accommodate the adapter, but no big deal for me, and probably isn't always necessary.
The Ultimate Digiscoping Adapters SCOPECAM ADAPTERS LIDS & TEES ACCESSORIES & MORE
scopecamadapter.com
Another option to reduce the problems others have mentioned from touching the camera to take pictures, is to set a timer. That's what I've been doing, 3 second timer, by the time the picture goes the scope is settled back in. I like the remote trigger idea for sure though.