UBVRI photometry of the pulsations in V2116Ophiuchi = GX1+4

The colours of pulsed and non-pulsed light in V2116Oph have been measured with the UBVRI photometer of the Laboratorio Nacional de Astrofisica, in Brazil. The symbiotic binary was in an optical bright state with v~17. If the blue component in the spectrum of V2116 Oph follows the prescription for a standard optically thick accretion disc spectrum, its contribution to the light of the system at 6600Angstroms is ~20 times the contribution of the red giant, with E(B-V)=2.1+/-0.1 mag and a distance of 8.3kpc. The pulsed component is estimated to have M_v~-1.7, implying characteristic sizes (for blackbody emission) of 1.4, 4.3 and 9.3Rsolar, for temperatures T_BB=100000, 20000 and 10000K, respectively.