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tokens: of these values, with discrepancies too large to be explained by instrumental errors (e.g. NGC 2509, Fig. 6 ). We also remark that on average, our distances estimated from parallaxes tend to agree more often with the more distant literature value. We suggest that the isochrone fitting procedure from which most photometric distances are estimated might be biased in many of those instances, as they might be affected by field contamination, as well as the degeneracies between distance, reddening, and metallicity. The strength of the Gaia data does not only reside in parallaxes from which distances can be inferred, and in precise and deep photometry, but also in our ability to obtain clean colour-magnitude diagrams from which astrophysical parameters can be infered. Fig. 6. Sky distribution ( top left panel ), colour-magnitude diagram ( top right panel ), and parallax as a function of magnitude ( bottom panel ) for the members of NGC 2509. The median parallax is 0.36 mas. Available literature distances for this cluster are 912 pc (DAML, blue), 1700 pc (MWSC, green) and 2900 pc ( Carraro Costa 2007 , red), which correspond to parallaxes of 1.09 mas, 0.59 mas, and 0.35 mas (respectively). 5. Specific remarks on some clusters It would be lengthy and impractical to devote a Section to every object under analysis in this study, but we provide additional comments on the specific cases of two clusters classified as OCs that are likely globular clusters, and on the previously unreported OCs discovered in this study. 5.1. BH 140 and FSR 1758 are globular clusters The colour-magnitude diagrams of BH 140 and FSR 1758 (shown in Fig. 7 ) present the typical aspect of globular clusters, with a prominent giant branch and an interrupted horizontal branch displaying a gap in the locus occupied by RR Lyrae. They are also clearly seen as rich and regular distributions on the sky. These two objects, located near the Galactic plane ( b = −4.3° and −3.3° for BH 140 and FSR 1758, respectively) also exhibit small parallaxes ( π = 0.16 mas and 0.09 mas), so their distances cannot be estimated accurately from parallaxes alone. FSR 1758, with a Galactic longitude l = 349.2°, seems to be located deep in the inner disk, as the distance estimated from its parallax yields a Galactocentric radius R GC = 1560 pc, and altitude Z = −470 pc. Fig. 7. Top left panel : colour-magnitude diagram for BH 140. Middle left panel : distribution on the sky for the same stars. Bottom left panel : proper motion diagram showing the field in light grey, and the cluster stars as black dots. Right column panel : same for FSR 1758. The broad appearance of the CMD of BH 140 can be explained by blended photometry in the inner regions. As discussed in Evans et al. (2018) and illustrated in Arenou et al. (2018) , the G BP and G RP fluxes of Gaia DR2 sources might be overestimated as a result of background contamination, and the effect is especially relevant in crowded fields such as the core of globular