We present a determination of the distance modulus of the globular cluster NGC 5904 ( M 5 ) , obtained by means of the subdwarf main–sequence fitting on the ( V , V - I ) color–magnitude diagram .
The subdwarf sample has been selected from the HIPPARCOS catalog in a metallicity range homogeneous with the cluster ( [ Fe/H ] \simeq - 1.1 ) .
Both the cluster and the subdwarfs have been observed with the same telescope+instrument+filters setup ( namely , ESO–NTT equipped with the SUSI2 camera ) , in order to preserve homogeneity and reduce systematic uncertainties .
A set of archival HST data has then been used to obtain a deep and precise ridge line .
These have been accurately calibrated in the ground photometric system by using the NTT data and used to fit the cluster distance modulus .
By adopting the most commonly accepted values for the reddening , E ( B - V ) = 0.035 and 0.03 , we obtain respectively \mu _ { 0 } = 14.44 \pm 0.09 \pm 0.07 and \mu _ { 0 } = 14.41 \pm 0.09 \pm 0.07 , in agreement with recent determinations .