Oscillation periods as a function of height of the magnetic dips. Top panels: models with θ = 45° and bottom panels: models with θ = 60°. Left and right panels: periods of the heavy and light prominence models, respectively. Red diamonds: longitudinal period; blue circles: vertical period due to the horizontal perturbation; green triangles: vertical period due to the vertical perturbation; and solid line: period from the theoretical pendulum model.