UBVRI photometric comparison sequences for symbiotic stars

We present accurate UBVRI photometric comparison sequences around 20 symbiotic stars. The sequences extend over wide brightness and color ranges, and are suited to cover quiescence as well as outburst phases. The sequences are intended to assist both present time photometry as well as measurement of photographic plates from historical archives. The types of variability presented by symbiotic stars are reviewed. Individual notes on the known photometric behaviour of the program stars are provided.