4 Residuals (Table 2) and accuracy of the measurements at the Cassegrain.

For comparison residuals to 147 orbits are given. Many a star was measured with both micrometers. Taking into account true deviations verified by several visual observers, speckle measurements or Hipparcos, the accuracy of the measurements is: for pairs with separations $0\hbox{$.\!\!^{\prime\prime}$}3$ to $1 \hbox{$.\!\!^{\prime\prime}$}0$: d theta $= \pm 2\hbox{$.\!\!^\circ$}1$, d rho $= \pm 0\hbox{$.\!\!^{\prime\prime}$}04$, for pairs $1 \hbox{$.\!\!^{\prime\prime}$}0$ to $2 \hbox{$.\!\!^{\prime\prime}$}0$: d theta $= \pm 1\hbox{$.\!\!^\circ$}1$, d rho $= \pm 0\hbox{$.\!\!^{\prime\prime}$}07$, for pairs exceeding $2 \hbox{$.\!\!^{\prime\prime}$}0$: d theta $= \pm 0\hbox{$.\!\!^\circ$}7$, d rho $= \pm 0\hbox{$.\!\!^{\prime\prime}$}07$.