M 11: A study of its inner and outer regions.

Two hundred and seventy-five new photographic V and B magnitudes based on the membership study of M11 by McNamara et al. (1977) are combined with earlier determined magnitudes by Johnson et al. (1956). The resulting color-magnitude diagram of M11 is one of the most complete yet produced for a galactic cluster. The cluster age and distance are determined to be about 200,000,000 yr and 1900 pc. The extensive halo surrounding this cluster, reported by McNamara and Sanders (1977), is confirmed and interesting differences between the CM diagrams of the inner and outer regions are discussed.