  The ytterbium atom is widely used in the fields of atomic physics, cavity
quantum electrodynamics, quantum information processing and optical frequency
standards. There is however a strong dispersion among the reported values of
the ${}^1{\rm S}_0 \rightarrow {}^1{\rm P}_1$ transition frequency. In this
article, we present two independent measurements of the absolute frequency of
this transition performed with two different wavemeters using atomic
fluorescence spectroscopy. The cancellation of Doppler shifts is obtained by
fine tuning the angle between the probe laser and the atomic beam. The
resulting $^{174}\mathrm{Yb}$ isotope transition frequency is estimated to be
$\,751\,526\,537\pm27$ MHz.
