UBVRI-KC Photometry of NGC~2323 and NGC~2539 Open Clusters
  The open clusters NGC 2323 and NGC 2539 have been analysed using CCD
UBV(RI)KC photometric data, observed at the San Pedro Martir Observatory.
Cluster memberships have been determined with the proper motion and parallax
measures from the GaiaDR2 astrometric data release. Photometric metal and heavy
element abundances have been obtained as (M/H, Z) = (-0.10, 0.012) (NGC 2323)
and (-0.31, 0.007) (NGC 2539), from the delta(U-B) technique in the two colour
diagrams, which are used to select the appropriate PARSEC isochrones.
  The estimated reddening of NGC 2323 is E(B-V) = 0.23+-0.04 using 11 early
type stars. For NGC 2539, we find E(B-V)= 0.02+-0.06. For (B-V) colour,
distance moduli and distances for NGC 2323 and NGC 2539 are derived as (V0-MV,
d (pc)) = (10.00+-0.10, 1000+-50) and (V0-MV, d (pc)) = (10.00+-0.04,1000+-20),
respectively.The median GaiaDR2 distance d=1000+-140 pc (plx=0.998+-0.136 mas)
for the likely members of NGC 2323 is in concordance with its four colour
photometric distances 910-1000 pc. For NGC 2539, its GaiaDR2 distance
d=1330+-250 pc (plx=0.751+-0.139 mas) is close to its four colour photometric
distances, 1000 pc.
  Fitting the PARSEC isochrones to the colour magnitude diagrams (CMDs) gives
an old age, 890+-110 Myr, for NGC 2539. Whereas NGC 2323 has an intermediate
age, 200+-50 Myr. One Red Clump Red Giant candidate (BD 12 2380) in the CMDs of
NGC 2539 has been confirmed as a member in terms of the distances dI = 950+-50
pc and dV =910+-90 pc of VI filters within the uncertainties, as compared to
the distance, 1000+-20 pc of NGC 2539. This giant's GaiaDR2 distance
(d=1200+-70 pc) is not close to these photometric distances.
