We present time resolved photometry and spectroscopy of the dwarf nova
V485 Cen. Significant radial velocity variations are detected in Ha o
nly for a period equal to the previously detected 59 min photometric p
eriod (Augusteijn et al. 1993), and we conclude that this is the orbit
al period of the system. Ha shows two components which vary with this
period. One component dominates the line wings and originates from a r
egion centered on the white dwarf. The second component dominates the
line center and originates in the hot spot (the so-called S-wave). Usi
ng various observational constraints we derive a mass ratio of q = M(W
D)/M(sec) similar to 2.6 and a inclination of i similar to 20-30 degre
es. Strong evidence is found for a significant contribution from the s
econdary to the spectrum at wavelengths longer than similar to 5900 An
gstrom. We discuss the discovery of a 59(m) orbital period in the fram
ework of evolutionary ideas about cataclysmic variables. The most like
ly explanation is that the secondary has a low, but finite, hydrogen c
ontent.