THE STELLAR CONTENT OF THE OPEN CLUSTERS TOMBAUGH-1 AND RUPRECHT-46

V and I CCD photometry has been carried out for two poorly known open clusters: Tombaugh 1 and Ruprecht 46. Photometry has also been obtaine d for nearby fields to correct for the effects of field star contamina tion. Estimates of the cluster fundamental parameters (reddening, dist ance and age) are given for Tombaugh 1 from comparison with theoretica l isochrones of the Padova group. We find that this is an intermediate -age open cluster about 1 Gyr old, and probably of solar abundance. Th e colour excess E(B-V) and the apparent distance modulus (m-M) are abo ut 0.40+/-0.05 and 13.60+/-0.20 mag, respectively. These results impro ve on previous determinations of the distance, and put Tombaugh 1 at a bout 3.0 kpc from the Sun. The high degree of contamination from field stars prevents us from obtaining firmer results. We estimate the clus ter radius to be about 4.0 arcmin. As for the luminosity function (LF) , there is satisfactory agreement with that derived from the standard Salpeter (x = 1.35) initial mass function (IMF), allowing for the unce rtainties in the subtraction of field stars. Ruprecht 46 was poorly st udied before. From our analysis it emerges that this object is not an open cluster, but simply a density fluctuation above the background le vel.