A study of the open cluster NGC 6811

We made 191 radial-velocity measurements for 60 late-type stars in a wide field of the open cluster NGC 6811 using a correlation spectrometer. Based on the similarity of their mean radial velocities (V_r) to the cluster velocity, we identified seven new members within 35 arcmin of the cluster center. Photoelectric UBVRI magnitudes were measured for 117 probable cluster members as identified by their proper motions (Sanders 1971). We refined the distance to the cluster (1040 pc) and estimated its age (7 x 10^8 years). Using the photometric data, we confirmed the cluster membership for 88 stars.