Angle I of the model by Iorio (2016) versus the time. The red diamonds are the values found from our dataset, while the green triangles are the two values derived by Iorio from the data available to him at the time of his work. We see that the precession rate dI∕dt is not constant as shown by the cubic interpolation plotted as a dotted red line. For the sake of comparison, we plot a linear interpolation between the two values available to Iorio assuming a constant precession rate.