Discovery of 17 variable stars in the old open cluster NGC 6791

We report results of photometric monitoring of the NGC 6791 field in V and B on four nights. We discovered eight contact binaries and nine other variables, with the majority of the latter (which are probably also binaries) observed in the region of the turn-off point of the cluster. The contact binaries seem to exhibit various stages of evolution, but two of them are blue stragglers. One of the variables is probably a binary composed of a red dwarf and a hot subdwarf.