  In this paper we apply a methodology, recently proposed by Bourouaine and
Perez (2019) (BP19), to interpret solar-wind turbulent power spectra beyond
Taylor approximation (TA). The turbulent power spectra were measured using
\emph{Helios} spacecraft data near 0.6 au. We use the model proposed in BP19 to
reproduce the field-perpendicular power spectrum $E(k_\perp)$ of anti-sunward
Alfv\'enic fluctuations in the plasma frame (where $k_\perp$ is the
field-perpendicular wavenumber) from the corresponding measured frequency power
spectrum $P_{\rm sc}(\omega,\theta_b)$ along the sampling angle $\theta_b$,
which is the angle between the local magnetic field and the sampling direction.
Here $\omega=2\pi f$ and $f$ is the frequency of the time signal. Interestingly
enough, we found that for all corresponding measured frequency power spectrum
$P_{\rm sc}(\omega,\theta_b)$ the reproduced field-perpendicular power spectrum
$E(k_\perp)$ is the same and independent of the considered sampling angle
$\theta_b$. This finding is consistent with the fact that the analyzed
turbulence is strong and highly anisotropic with $k_\| \ll k_\perp$ (where
$k_\|$ is the field-parallel wavenumber). Furthermore, for this specific time
signal we found that the commonly used TA is still approximately valid with the
important difference that a broadening in $k_\perp$ for each angular frequency
$\omega$ is present. This broadening can be described in the context of the
methodology proposed in BP19.
