UBVI CCD photometry is obtained for the open clusters NGC 4609 and Hogg 15 in
Crux. For NGC 4609, CCD data are presented for the first time. From new
photometry we derive the reddening, distance modulus and age of each cluster -
NGC 4609 : E(B-V) = 0.37 +/- 0.03, V_0 - M_V = 10.60 +/- 0.08, log tau = 7.7
+/- 0.1; Hogg 15 : E(B-V) = 1.13 +/- 0.11, V_0 - M_V = 12.50 +/- 0.15, log tau
<= 6.6. The young age of Hogg 15 strongly implies that WR 47 is a member of the
cluster. We have also determined the mass function of these clusters and have
obtained a normal slope (Gamma = -1.2 +/- 0.3) for NGC 4609 and a somewhat
shallow slope (Gamma = -0.95 +/- 0.5) for Hogg 15.Comment: 12 pages, 14 figures, JKAS, in pres
