5 Discussion and conclusions

Photometric data presented above show that Tr 5 is a rich old open cluster. The cluster age is slightly lower than the age of M 67. By assuming solar metallicity of the cluster we estimated its unreddened distance moduli and reddening at (m-M)₀=12.4 and E(B-V)=0.58, respectively. The cluster is located in the galactic anticenter and therefore its metallicity is likely to be lower than the solar value. In that case its unreddened distance modulus would be lower than 12.4 and reddening E(B-V) would be higher than 0.58. Independent spectroscopic determination of metallicity of the cluster is needed to allow a more precise estimate of its parameters. Tr 5 is a relatively rich object in comparison with other known old open clusters. Our data imply 3000 $m_{\odot}$ as a conservative lower limit on the cluster mass.