Separation between θ ¹ Ori B ₁ and the barycenter of the B ₂ B ₃ binary. Note how over 15 yr of observation there has been a small, yet significant, relative proper motion observed (0.80 ± 0.18 mas yr ⁻¹; which is a significant correlation at the 97.4% level). The first two data points are speckle observations from the 6 m SAO telescope (Weigelt et al. 1999), the next point is from Gemini/Hokupa'a observations Close et al. (2003b) followed by MMT AO observations Close et al. (2003b), and then LBT Close et al. (2012b), and the last from the MagAO system (this study).