In order to avoid the Sun entering in its field of view, during the northern summer CoRoT observed in an area around Serpens Cauda, toward the galactic center, and during the winter it observed in Monoceros, in the Galactic anticenter. Both these "eyes" of CoRoT have been studied in preliminary observations carried out between 1998 and 2005, allowing the creation of a database, called CoRoTsky, with data about the stars located in these two patches of sky. This allowed selecting the best fields for observation: the exoplanet research program requires a large number of dwarf stars to be monitored, and to avoid giant stars, for which planetary transits are too shallow to be detectable. The asteroseismic program required stars brighter than magnitude 9, and to cover as many different types of stars as possible. In addition, in order to optimize the observations, the fields shouldn't be too sparse – fewer targets observed – or too crowded – too many stars overlapping.