  We present here a detailed calculation of opacities for Fe~XVII at the
physical conditions corresponding to the base of the Solar convection zone.
Many ingredients are involved in the calculation of opacities. We review the
impact of each ingredient on the final monochromatic and mean opacities
(Rosseland and Planck). The necessary atomic data were calculated with the
$R$-matrix and the distorted-wave (DW) methods. We study the effect of
broadening, of resolution, of the extent of configuration sets and of
configuration interaction to understand the differences between several
theoretical predictions as well as the existing large disagreement with
measurements. New Dirac $R$-matrix calculations including all configurations up
to the $n=$ 4, 5 and $6$ complexes have been performed as well as corresponding
Breit--Pauli DW calculations. The DW calculations have been extended to include
autoionizing initial levels. A quantitative contrast is made between comparable
DW and $R$-matrix models. We have reached self-convergence with $n=6$
$R$-matrix and DW calculations. Populations in autoionizing initial levels
contribute significantly to the opacities and should not be neglected. The
$R$-matrix and DW results are consistent under the similar treatment of
resonance broadening. The comparison with the experiment shows a persistent
difference in the continuum while the filling of the windows shows some
improvement. The present study defines our path to the next generation of
opacities and opacity tables for stellar modeling.
