1995A&AS..109..479S

A color-magnitude diagram for the galactic globular cluster NGC 4833, based on the photographic BV photometry of about 868 stars in a 12'x12' field with an automatic measuring machine, is presented. It reaches the cluster main sequence turn-off point at V≃19.2mag ; the difference in V magnitudes between the turn-off and the horizontal branch being normal. This diagram, reaching near three magnitudes fainter is clearly an improvement over the only two previous CMDs available in the literature, both published more than two decades ago by Alcaino [A&A 13 (1971) 287] and Menzies [MNRAS 156 (1972) 207], from photographic photometry reduced with an iris photometer down to V≃16.5. Indications have been found of the presence of a red giant branch bump, approximately at the same position with respect to the horizontal branch and main sequence turn-off as in NGC 5897. There is also some hint of the deficiency of stellar population of the subgiant branch just above the turn-off point, similar to that observed in some other metal-poor globular clusters.