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.
	
	
		
			
				
			
			
				
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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.