SIMBAD references

The long and continuous high-time-resolution coverage of many stars by the Kepler and TESS space missions permit to explore periodic phenomena with a much higher precision than is possible with terrestrial observations. This includes the most basic property of binary stars, namely the orbital period. Here, I use TESS and Kepler light curves, sometimes in connection with other archival data and information taken from the literature, to improve or to correct the orbital periods of 53 cataclysmic variables with previously known periods. For 13 and 26 objects a significant or an incremental improvement, respectively, could be achieved. The periods of two systems that in the past had been only inferred indirectly were measured directly for the first time. In a remarkable 23% (12 stars) of all investigated systems previously reported orbital periods are shown to be wrong and require correction. Other interesting features seen in the light curves of some of the cataclysmic variables are briefly mentioned, but a more detailed investigation is postponed to future work.