Abstract
A comparison of the colour-magnitude diagrams (CMDs) and the main sequence luminosity function (LF) of five young Galactic star clusters and four young Large Magellanic Cloud star clusters derived from precise CCD observations has been made with the synthetic CMDs derived from the recent theoretical stellar evolutionary models. Some gaps in the brighter part of the cluster main sequence have been identified. A comparison of the synthetic CMDs with the observed ones indicates that the overshoot models should be preferred over classical models. The synthetic integrated LFs from the models can be matched with the observed LFs by varying the value of mass function slope and binary fraction. In comparison to classical models, overshoot models estimate older ages but slightly heavier turn-off mass for the clusters.
