We present results of non-simultaneous time-resolved photometric and spectroscopic observations of the little-studied dwarf nova FS Aur in quiescence .
The spectrum of FS Aur shows strong and broad emission lines of hydrogen and He I , and of weaker He II \lambda 4686 and C III/N III blend , similar to other quiescent dwarf novae .
All emission lines are single-peaked , however their form varies with orbital phase .
Absorption lines from a late-type secondary are not detected .
From the radial velocity measurements of the hydrogen lines H _ { \beta } and H _ { \gamma } we determined a most probable orbital period P=0 \aas@@fstack { d } 059 \pm 0 \aas@@fstack { d } 002 .
This period agrees well with the 0 \aas@@fstack { d } 0595 \pm 0 \aas@@fstack { d } 0001 estimate by Thorstensen et al .
( 1996 ) .
On the other hand , the period of photometric modulations is longer than the spectroscopic period and can be estimated as 3 hours .
Longer time coverage during a single night is needed to resolve this problem .
Using the semi-amplitude of the radial velocities , obtained from measurements of hydrogen and helium lines , and some empirical and theoretical relations we limited the basic parameters of the system : a mass ratio q \geq 0.22 , a primary mass M _ { 1 } = 0.34 - 0.46 M _ { \sun } , a secondary mass M _ { 2 } \leq 0.1 M _ { \sun } , and an inclination angle i = 51 ^ { \circ } -65 ^ { \circ } .
Doppler tomography has shown at least two bright regions in the accretion disk of FS Aur .
The first , brighter spot is located at phase about 0.6 .
The second spot is located opposite the first one and occupies an extensive area at phases about 0.85 - 1.15 .