Age determination for 269 $Gaia$ DR2 Open Clusters
  $Context$. Gaia Second Data Release provides precise astrometry and
photometry for more than 1.3 billion sources. This catalog opens a new era
concerning the characterization of open clusters and test stellar models,
paving the way for a better understanding of the disc properties. $Aims$. The
aim of the paper is to improve the knowledge of cluster parameters, using only
the unprecedented quality of the Gaia photometry and astrometry. $Methods$. We
make use of the membership determination based on the precise Gaia astrometry
and photometry. We apply anautomated Bayesian tool, BASE-9, to fit stellar
isochrones on the observed G, GBP, GRP magnitudes of the high probability
member stars. $Results$. We derive parameters such as age, distance modulus and
extinction for a sample of 269 open clusters, selecting only low reddening
objects and discarding very young clusters, for which techniques other than
isochrone-fitting are more suitable for estimating ages.
