Variation of the radial action as a function of integration time for spherical potentials. The radial action is computed at each point along an orbit with the same initial condition as the orbit displayed on the right in Figure 10, but integrated in an IsochronePotential with scale parameter 0.3 (this isochrone potential has a similar rotation curve as MWPotential2014 over the extent of the orbit shown in Figure 10). The radial action is computed by using the analytic formulae for an isochrone potential (Binney & Tremaine 2008) using an actionAngleIsochrone instance and by numerical integration using an actionAngleSpherical object. The radial and vertical actions for this orbit are 0.05 and 0.025, respectively. The radial action is conserved to 1 part in 10⁻⁸.