  We obtained thirteen spectropolarimetric observations of the strongly
magnetic rapidly oscillating Ap star HD154708 over three months with the
multi-mode instrument FORS1, installed at the 8-m Kueyen telescope of the VLT.
These observations have been used for the determination of the rotation period
of P=5.3666+-0.0007d. Using stellar fundamental parameters and the longitudinal
magnetic field phase curve, we briefly discuss the magnetic field geometry. The
star is observed nearly pole-on and the magnetic field geometry can be
described by a centred dipole with a surface polar magnetic field strength B_d
between 26.1 and 28.8kG and an inclination of the magnetic axis to the rotation
axis in the range 22.5deg to 35.5deg.
