Optical Monitoring of Quasistellar Objects. I

Observational results of 25 quasistellar objects (QSO's) from the Yale Observatory optical patrol program of QSO's are given. Light curves and magnitudes are presented for all objects, generally brighter than 17th magnitude. The program covered a period of about five years, during which time more than a thousand observations were obtained. Fine-structure light curves are given for 3C 345 and 3C 454.3. A color correc- tion between Yale photographic magnitude and Johnson's B-magnitude is suggested. There is a good correlation of optical variation with the radio variability at 2-cm to 6-cm wavelength. From the Yale observations, at least 25% to 30% of the QSO's are varying, with an amplitude of greater than 1.0 mag, and 50% of the other objects on the Yale list are variables whose magnitude has changed by more than 0.3 mag. The remaining objects have no significant variation, although in several occasions variations have been detected in the earlier investigations. No apparent periodicities can be established from the last five years of observations which may either indicate that the duration of the observation was not long enough to detect periods, or that the variable characteristics of QSOs are probably different from pulsars.