Resulting J₂ values of polytropic models of rigidly rotating Jupiter for q = 0.089195487 (left) as in H13 and Wisdom & Hubbard (2016), and for q = 0.088570679 (right) as in Wisdom (1996). Blue symbols: using ToF to fourth order, blue lines: respective fit curves, light blue: same as blue but using ToF 3, red symbols: using CMS method. Reference values are in black; black circle: CMS results of H13 for N = 512, horizontal black lines: unknown value of N, in particular: thick black lines: Bessel/CLC results of Wisdom & Hubbard (2016), thin black lines: ToF 3 results of H13 and Wisdom (1996). The vertical black arrow shows the current Juno uncertainty of J₂ (Folkner et al. 2017), here arbitrarily placed. The x-axis is number of radial grid points N.