For an Angle of Approach to exist, you need Two Points. First, the "Impact-Separation" Point, and second, the point at which the Club was designed to produce Straight-Away Flight without manipulation of Hook Face - LP(Low Point).
interesting. Can you support this? Its not in the book. Is it in the audio tapes? Not saying I disagree .... just wondering.
Also isn't the Angle of Approach a Visual Equivalent? Meaning its only visible from the golfers eye line?