  The high-resolution B$^1\Sigma^+$ - A$^1\Pi$ (0, 0) and (0, 3) emission bands
of the less-abundant $^{13}$C$^{17}$O isotopologue have been investigated by
Fourier-transform spectroscopy in the visible region using a Bruker IFS 125HR
spectrometer at an accuracy 0.003 cm$^{-1}$. These spectra are combined with
high-resolution photoabsorption measurements of the $^{13}$C$^{17}$O
B$^1\Sigma^+$ $\leftarrow$ X$^1\Sigma^+$ (0, 0), B$^1\Sigma^+$ $\leftarrow$
X$^1\Sigma^+$ (1, 0) and C$^1\Sigma^+$ $\leftarrow$ X$^1\Sigma^+$ (0, 0) bands
recorded with an accuracy of 0.01 cm$^{-1}$ using the vacuum ultraviolet
Fourier-transform spectrometer, installed on the DESIRS beamline at the SOLEIL
synchrotron. In the studied 17,950 - 22,500 cm$^{-1}$ and 86,800 - 92,100
cm$^{-1}$ regions, 480 transitions have been measured. These new experimental
data were combined with data from the C $\to$ A and B $\to$ A systems,
previously analyzed in 13C17O. The frequencies of 1003 transitions derived from
12 bands were used to analyze the perturbations between the A$^1\Pi$ ($\nu$ = 0
- 3) levels and rovibrational levels of the d$^3\Delta_i$, e$^3\Sigma^-$,
a$'{}^3\Sigma^+$, I$^1\Sigma^-$ and D$^1\Delta$ states as well as to a
preliminary investigation of weak irregularities that appear in the
B$^1\Sigma^+$ ($\nu$ = 0) level. Deperturbed molecular constants and term
values of the A$^1\Pi$ state were obtained. The spin-orbit and L-uncoupling
interaction parameters as well as isotopologue-independent spin-orbit and
rotation-electronic perturbation parameters were derived.
