Peak of the VHE emission in terms of the super-orbital phase defined in radio. Each data point represents the peak flux emitted in one orbital period during orbital phases 0.5–0.75 and is folded into the super-orbit of 1667 days known from radio observations (Gregory 2002). MAGIC (magenta dots) and VERITAS (blue squares) points have been used in this analysis. The fit with a sinusoidal (solid red line), with a step function (solid green line), and with a constant (solid blue line) are also represented. The gray dashed line represents 10% of the Crab Nebula flux, the gray solid line the zero level for reference.