iOptron Smartphone Eyepiece Adaptor (Red)

Nice Smart Phone Holder but Crummy Eyepiece

I purchased the Ioptron Smart Phone Eyepiece Adaptor to use with my f/5.5 APO refractor. I thought it would be perfect for the public star parties hosted by our Astronomy Club. The mechanism that hold the Smart Phone to the eyepiece is elegant and simple. I found that it is best to remove the shock resistant case from the phone before mounting. There is enough give in the case to keep the phone centered on the exit pupil of the eyepiece. This is critical. A 12.5 mm Ioptron eyepiece is threaded into the phone mount. Because of this threaded attachment, the setup only works with the Ioptron eyepiece. Unfortunately this eyepiece is of fairly poor quality. Look at the attached photos of a neighbor's roof taken with the Ioptron Adapter and eyepiece and those I took with the phone hand-held over two different premium eyepieces. The Ioptron eyepiece show terrible field curvature. The useful field of view extents only to about half way to the field stop on the eyepiece. Okay, the Televue eyepieces I use for this comparison each cost about 5 times that of the Phone Adaptor and eyepiece, but I have become fond of the wide flat fields that the premium eyepieces can deliver. It would be great if the Smart Phone Adapter could be used with these eyepieces but it cannot.