A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Norm Goldblatt
Date: 2015 Aug 11, 15:43 -0700
Frank and Greg- Here's the photo I used to try to calibrate my iPhone 5s. This is all very interesting. The data I took using this photo showed a wide range of calibration constants. I could have made mistakes and I'll check it again. I did find a reference to field distortion for the 5s and it looks great I also include this. Oh, the date taken- 7/6/2015 10:34 PM. My method is different from Greg's. I calculated the angular distance between all pairs of stars and compared it to the photographic position using ImageJ.
Off this topic, I've processed my sextant measurements of Venus-Jupiter angular distance over the month of July and I'm quite pleased. Will 'publish' them later for anyone interested.
So glad I met all you folks.