Abstract
Photographic observations of the quasar 3C345 during 1968 and 1969 are reported. They show a quiescent state during 1968 and renewed activity in 1969. Fourier analysis of all available brightness measurements 1965–69 shows a dominant long-term variation with an apparent period of 1025 d, and two weak components with periods of 165 d and 556 d. There are no conspicuous short-period components down to 10 d. The light-curve synthesized from these three components does not fully represent the rapid variations, but does suggest a period of 165 d for the optical spikes, which is probably related to the periods of 80 d and 320 d suggested earlier.
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Smyth, M.J., Wolstencroft, R.D. The optical variability of 3C345. Astrophys Space Sci 8, 471–477 (1970). https://doi.org/10.1007/BF00651339
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DOI: https://doi.org/10.1007/BF00651339