it can be considered a very clear signal in the telemetry data that deserves further analysis. The difference among the model and the data is sufficiently accurate to allow for a determination of the components of the acceleration field responsible for this deviation of the spacecraft from the predicted trajectory. This is achieved by using a fourth-order central finite difference method [@Fornberg]: $$\label{deltaa}
\begin{array}{rcl}
\delta{\bf a}&=&\displaystyle\frac{1}{h^2} \,\left\{ -\displaystyle\frac{1}{12}\left( \delta {\bf r}(t - 2 h)+
\delta {\bf r}(t+2 h)\right)\right. \\
\noalign{\smallskip}
 &+&\displaystyle\frac{4}{3}\left( \delta {\bf r}(t-h)+\delta {\bf r}(t+h) \right)-
\left. \displaystyle\frac{5}{2} \delta {\bf r}(t)\right\} \\
\noalign{\smallskip}
&-&\displaystyle\frac{1}{90} \displaystyle\frac{d^6 \delta {\bf r}}{d t^6} \, h^4+ {\mathcal O}\left(h^5\right) \; ,
\end{array}$$ where $h$ is the timestep and the error term can be estimated by using the corresponding approximation for the sixth-order derivative. As the data provided for the spacecraft tracking is separated by one minute intervals [@Horizons] we should also choose $h=1$ min to allow for the evaluation of Eq. (\[deltaa\]) with the same accuracy.

![Radial component of the anomalous acceleration acting upon the Juno spacecraft during the perijove manoeuvre. The solid line corresponds to the first flyby and the open circles to the third one.[]{data-label="fig6"}](Figure6.eps){width="\columnwidth"}

![The same as Fig. \[fig6\] but for the 