(a) Comparison of our measured values of μ_α and those of S. van den Bergh & K. Kamper (1985). (b) Similar comparison for μ_δ. For the μ_δ values from van den Bergh and Kamper, we subtracted 0﹩\mathop{.}\limits^{\unicode{x02033}}﹩008 to account for the proper motion of reference stars in their work (S. van den Bergh & K. Kamper 1985). In both panels, the dashed line indicates where the two measured values are equal.