  We report on Doppler-free continuous-wave optical UV-spectroscopy resolving
the hyperfine structure of the $\mathrm{A}\,^2\Sigma^+ \leftarrow
\mathrm{X}\,^2\Pi_{3/2}$ transition in nitric oxide for total angular momenta
$J_X=1.5-19.5$ on the $\mathrm{oP_{12ee}}$ branch. The resulting line
splittings are compared to calculated splittings and fitted determining new
values for the molecular constants $b, c, eQq_0$ and $b_F$ for the
$\mathrm{A}\,^2\Sigma^+$ state. The constants are in good agreement with values
previously determined by quantum beat spectroscopy.
