About the dependency of the spin maxima on orbital phase in the intermediate polar MU Cam

Long term monitoring of intermediate polars is performed as part of the Inter-Longitude Astronomy campaign. High-quality and long time series observations allow us to investigate fine effects on complex light curves. In the case of MU Cam we have investigated the periodic modulation of the spin phases with the orbital phase. This dependency was already described by Kim et al. (2005). As an explanation they proposed inhomogeneous accretion flow from the secondary. However, based on our new data, we propose as a simple explanation the influence of orbital sidebands in the periodic signal produced by the intermediate polar. This explanation is supported by the fact that the changes in spin maxima phase are observed mainly when the sideband frequency is dominant in the periodogram.