NGC 6866 variables V and I light curves

We find 28 periodic variables, of which 19 are newly identified. The periods of these variables, which have V magnitudes from 11.5 to 19.3mag, range from ~48min to 37d.

We detected several {delta} Scuti stars, some of which are of high amplitude, as well as {gamma} Doradus and rotational variables, and eclipsing binaries. In order to study the physical properties of the cluster, we obtained UBVRI photometry of all the stars on a good photometric night. The radial distribution of the stellar surface density shows that the cluster has a radial extent of about 7-arcmin ( ~3pc) with a peak density of 5.7+/-0.7stars/arcmin^2^ at the cluster centre.