Best-fit orbit (blue; rotation counterclockwise) of the six unambiguous epochs (C, D, F, G, H, and I), marked by yellow crosses and error bars. The error is the 1σ confidence interval of the positions given in Table 1. Most error bars are smaller than the representing crosses. The dashed line represents the line of nodes, and the dotted line connects peri- and apoastron. The χ²-maps of the positions of the secondary for epochs A, B, and E are shown in green, red, and purple, respectively. Encircled are the local minima that visually match the derived orbit the best, with the center of each circle at the expected position for each epoch.