Mean longitudinal magnetic field (top left), crossover (bottom left), mean quadratic magnetic field (top right), and mean magnetic field modulus (bottom right) of the star HD 166473, against heliocentric Julian date. A diamond is used to represent the measurement of Mathys et al. (2007) obtained with the UVES spectrograph at Unit Telescope 2 of ESO’s Very Large Telescope. All other additional measurements of these authors are based on observations performed with instrumental configurations similar to those used for the present study; the same symbols are used to identify them as in the rest of this paper (see beginning of Appendix A.