The BV light and O-C curves analyses of the triple system V505 Sagittarii

The new UBV light curves and times of minimum light for V505 Sgr are presen ted. The B and V band light curves were analyzed by the Wilson-Devinney cod e and the contribution of the third star to the total light of the triple s ystem was found to be 2.62% for the B and 3.56% for V band. The colour and absolute visual magnitude of the third star were estimated to be 0(m) .46 a nd 4(m) .00, respectively The apparent visual magnitude of the third star s eems fainter by about 3(m) .6 than the eclipsing pair. Only photoelectric t imes of minimum light were used to determine the parameters for the light-t ime orbit. The semi-major axis of the third star's orbit around the eclipsi ng pair was found to be 18.8 AU. The third body completes a revolution on t his orbit in 38.13 yr. The semi-amplitude of the radial velocity of the ecl ipsing pair's mass center was estimated to be 2.37 km s(-1) while 6.4 km s( -1) was found for the third star which agrees with the spectroscopic measur ements.