\, \hat{\bm{r}}+\mathcal{F}_\theta \, \hat{\bm{\theta}}$, with $\hat{\bm{r}}$ and $\hat{\bm{\theta}}$ as the unit radial and polar vectors. In order to calculate this force we must know the orientation of the axis of Jupiter in the ecliptic frame of reference. The right ascension, $\alpha_J$, and declination, $\delta_J$, of the unit vector pointing in the direction of this axis vary with time as a consequence of precession and nutation and it is given by [@Jupiterfacts]: $$\begin{aligned}
\label{EqaxisJ}
\alpha_J &=& 268.057 - 0.006\, T\; ,\\
\noalign{\smallskip}
\delta_J &=& 64.495 + 0.002\, T\; ,\end{aligned}$$ where $T$ is the time in Julian years from the J2000 reference date (Julian day $2451545.0$). For the first flyby of Jupiter on August 27th, 2016 we have $T=0.0166516$ Julian years and this allows for a determination of the axis orientation in the Earth’s equatorial frame of reference with an accuracy of $0.001$ sexagesimal degrees. The obliquity of the ecliptic is also known with high accuracy at a given Julian date in terms of the following polynomial in $T$ [@Almanac]: $$\label{oblq}
\begin{array}{rcl}
\chi&=& 23^\circ 26^{'} 21.406^{''}-46.836769^{''} T \\
\noalign{\smallskip}
&-&0.0001831^{''} T^2+0.00200340^{''} T^3 \\
\noalign{\smallskip}
&-&5.76^{''}\times 10^{-7} T^4-4.34^{''} \times  10^{-8} T^5\; .
\end{array}$$ From Eqs. (\[EqaxisJ\]) and (\[oblq\]) we have calculated the components 