Preliminary study of the Old open Cluster NGC 6192

Abstract

NGC 6192 is an old open cluster (of 6`.8 radius) with turn-off at about Mv = 2.2, corresponding to an age of 9 X 10/sup8/ yr. It has a mean colour excess of 0.26 plus or minus 0.08 (s.d., 11 stars) and a distance of 890 plus or minus 130 pc. It appears to have an excess of gaints compared to the Hyades, and also a main sequence to at least V = 18 or Mv = 7. The cluster appears superimposed, but not centreed, on a concentration of B stars with mean colour excess, E/sub/B-V - 1.14 plus or minus 0.24 (29 stars) and distance 4.0 plus or minus 0.5 kpc. Since these conclusions are based on photographic photometry calibrated with only 14 of 22 stars measured photoelectrically in the UBV, these results must be treated with caution, but certainly justify further photoelectric and spectroscopic work on the cluster