Close-up view of Fig. 1 shows the best elliptical fit (black ellipse) and ellipses within 1-σ region (grey) to the ten chords derived from the timings in Table A.1. The grey 1-σ fits differ only slightly from the black best-fit. The red segments represent the 1-σ error bars in the ingress and egress times. At this scale, the Gemini and CFHT chords are superimposed, and their error bars would be too small to be seen (i.e., they are here represented by red squares, much bigger than their actual sizes).