UBVRI photometry of Nova PW Vulpeculae 1984

UBVRI light curves of Nova PW Vulpeculae have been obtained over the interval 1984 August 2 to December 24. The principal features of these data are the following: (1) a gradual trend to the blue in B-V and R-I, and to the red in V-R the latter is probably due to the increasing dominance of the R band by H α emission; (2) an abrupt decrease immediately after maximum light, which occurred progressively later at longer wavelengths; and (3) fluctuations in light, but not in colour, which were quasi-periodic on a time-scale of 16 d. Comparisons between our UBV data and other photoelectrically measured mgnitudes show satisfactory agreement, and indicate that the fluctuations are genuine, and not due to observational errors. Fairly satisfactory agreement is also obtained between the V magnitudes and published visual observations, but some differences are noted. No other observations of PW Vul in the R and I bands are known to us. The fluctuations conspire to make very unreliable any estimate of the distance of the nova from the mean rate of decline.