  The results of CCD photometric survey performed with the 90/180 cm
Schmidt-Cassegrain Telescope of the Nicolaus Copernicus University Astronomical
Observatory in Piwnice (Poland) and the 70/172 cm Schmidt Telescope of the
National Astronomical Observatory (NAO) at Rozhen (Bulgaria) of the field of 1
Gyr old open cluster NGC 6939 are presented. Twenty two variable stars were
detected, four of them previously known. Four eclipsing systems (3 detached and
1 contact binary) were found to be members of the cluster. Analysis of the
brightness of the contact binary V20 strongly supports the distance to the
cluster of 1.74 +/- 0.20 kpc. The small population of contact binaries in NGC
6939 confirms also the relatively young age of the cluster.
