Review on Universal Cell Phone Mount for Telescopes, Binoculars, Monoculars, Microscopes and Spotting Scopes - Smartphone Adapter Holder Clip Bracket Compatible with Most Mobile Phones by Lance Harrison

I found this adapter easier to use than some other inexpensive phone holders. The part that attaches to the telescope lens is a little clunky and the phone holder isn't as secure as I would have liked, but the adapter helps keep the phone level and the eyepiece pressed firmly against the eyepiece. This greatly simplifies pointing the phone camera through the eyepiece. You still need to adjust the eyepiece cutout and overall focus, but those controls are on your telescope, not on this adapter. You probably won't get a full frame in your phone's camera app unless you use a digital zoom to fill the frame.