UBV ( RI ) _ { C } CCD photometry of a 2. ^ { \prime } 1 \times 3. ^ { \prime } 3 field centered on the young open cluster Haffner 18 is presented and discussed .
Spectroscopic classification of seven stars is also provided .
44 clusters members are identified , the earliest type being O6 .
The distance to the cluster is found to be 6.3 kpc , corresponding to a galactocentric distance of 12.7 kpc ( for a Sun galactocentric distance of 8.5 kpc ) .
Excellent fit to the observed main sequence is achieved by a solar composition isochrone of 2 \times 10 ^ { 6 } years reddened by E _ { B - V } =0.62 mag .
Differential reddening of intra–cluster origin is present .
Pre-main sequence members are likely to be present over the 6 mag range explored by our observations ( reaching down to earliest A spectral types ) .
The presence of differential reddening and pre-main sequence members agrees with the evidence for a bright parent nebulosity embedding the whole cluster .
The radial velocity of the cluster is consistent with the Hron ( 1987 ) model of galactic rotation .