We present the results of 26 nights of CCD photometry of the nova V2540 Oph
(2002) from 2003 and 2004. We find a period of 0.284781 +/- 0.000006 d (6.8347
+/- 0.0001 h) in the data. Since this period was present in the light curves
taken in both years, with no apparent change in its value or amplitude, we
interpret it as the orbital period of the nova binary system. The mass-period
relation for cataclysmic variables yields a secondary mass of about 0.75 +/-
0.04 Msun. From maximum magnitude - rate of decline relation, we estimate a
maximum absolute visual magnitude of M(V)=-6.2 +/- 0.4 mag. This value leads to
an uncorrected distance modulus of (m-M) = 14.7 +/- 0.7. By using the
interstellar reddening for the location of V2540 Oph, we find a rough estimate
for the distance of 5.2 +/- 0.8 kpc. We propose that V2540 Oph is either: 1) a
high inclination cataclysmic variable showing a reflection effect of the
secondary star, or having a spiral structure in the accretion disc, 2) a high
inclination intermediate polar system, or less likely 3) a polar.Comment: 8 pages, 7 figures, accepted by PAS