  We searched for potential atmospheric species in KELT-10b, focusing on sodium
doublet lines (Na i; 589 nm) and the Balmer alpha line (H $\alpha$; 656 nm) in
the transmission spectrum. Furthermore, we measured the planet-orbital
alignment with the spin of its host star. We used the Rossiter-McLaughlin
Revolutions technique to analyze the local stellar lines occulted by the planet
during its transit. We used the standard transmission spectroscopy method to
probe the planetary atmosphere, including the correction for telluric lines and
the Rossiter-McLaughlin effect on the spectra. We analyzed two new light curves
jointly with the public photometry observations. We do not detect signals in
the Na i and H $\alpha$ lines within the uncertainty of our measurements. We
derive the 3-sigma upper limit of excess absorption due to the planetary
atmosphere corresponding to equivalent height Rp to 1.8Rp (Na i) and 1.9Rp (H
$\alpha$). The analysis of the Rossiter-McLaughlin effect yields the
sky-projected spin-orbit angle of the system $\lambda$ = -5.2 $\pm$ 3.4 and the
stellar projected equatorial velocity $v_{eq} \sin{i_\star}$ = 2.58 $\pm$ 0.12
km/s. Photometry results are compatible within 1 -sigma with previous studies.
We found no evidence of Na i and H $\alpha$, within the precision of our data,
in the atmosphere of KELT-10b. Our detection limits allow us to rule out the
presence of neutral sodium or excited hydrogen in an escaping extended
atmosphere around KELT-10b. We cannot confirm the previous detection of Na i at
lower altitudes with VLT/UVES. We note, however, that the Rossiter-McLaughlin
effect impacts the transmission spectrum on a smaller scale than the previous
detection with UVES. Analysis of the planet-occulted stellar lines shows the
sky-projected alignment of the system, which is likely truly aligned due to
tidal interactions of the planet with its cool (Teff < 6250 K) host star.
