Isolines ℋ′ = C on a unit sphere for the Colombo top model with I = 5° and κ = −0.914; since | κ | >κ_⋆ ≃ 0.652 there are four stationary (Cassini) equilibria of the flow denoted by symbols and labeled C₁ to C₄. The resonant zone about C₂ is highlighted by gray shading. The four panels show different angles of view; the coordinate grid is such that colatitude ε is measured from the north pole near C₁, and the longitude ϕ is measured from the meridian of the C₂ equilibrium.