  We present new optical and infrared photometric observations and high
resolution H$\alpha$ spectra of the periodic radio star \lsi. The optical
photometric data set covers the time interval 1985-1993 and amounts to about a
hundred nights. A period of $\sim$26 days is found in the V band. The infrared
data also present evidence for a similar periodicity, but with higher amplitude
of variation (0\rmag 2). The spectroscopic observations include 16 intermediate
and high dispersion spectra of \lsi\ collected between January 1989 and
February 1993. The H$\alpha$ emission line profile and its variations are
analyzed. Several emission line parameters -- among them the H$\alpha$ EW and
the width of the H$\alpha$ red hump -- change strongly at or close to radio
maximum, and may exhibit periodic variability. We also observe a significant
change in the peak separation. The H$\alpha$ profile of \lsi\ does not seem
peculiar for a Be star. However, several of the observed variations of the
H$\alpha$ profile can probably be associated with the presence of the compact,
secondary star.
