Magellanic Cloud Investigations: II. 47 Tucanae

Photographic photometry for 255 stars in B and V is combined with existing photoelectric data to define the colour–magnitude diagram of 47 Tuc down to well on to the main sequence. The previous paper in this series considered the main-sequence fit of 47 Tuc for modulus determination and placed the median luminosity of cluster-type variables at M V = + 0.55. The 47 Tuc horizontal branch shows a very well-defined concentration well to the red of the cluster-type variable zone. A single very blue star (probably on the horizontal branch) has been observed in the region studied. Comparisons between clusters with different metal abundances indicate a progressive change in the transition from the main sequence to the subgiant sequence, but do not support a dependence of the luminosity of cluster-type variables on abundances.