2002A&A...385..533K

The hipparcos and tycho catalogues have proven to be a very powerful source for detection of variability in stars. The photometric errors for individual measurements are typically of the order of a few millimagnitudes. Amplitudes for periodic variability of stars and based on hipparcos data are published which are of the same order. An example could be the still controversial case of ETAnd (Scholz et al., 1998A&A...337..447S; Weiss et al., 1998A&A...338..919W) with contradicting evidence for hipparcos and ground-based observations. Another case could be the AGB star RVCam (Kerschbaum et al., 2001A&A...375..527K) with a similar contradiction. In this paper we investigate the properties of hipparcos photometry for a set of 4863 presumably constant stars and we determine the frequency ranges of hipparcos which seem to be affected by the instrument.