RGB image (red = K_s band, green = H band and blue = J band) of the central catalogue corresponding to fields from 1 to 30. Field 7 is not included in J band since the observing conditions were not acceptable to include it in the survey. The insets show the NSC (e.g. Launhardt et al. 2002; Schödel et al. 2014; Boehle et al. 2016; Gravity Collaboration 2018), the Arches cluster (e.g. Martins et al. 2008; Clarkson et al. 2012), the Quintuplet cluster (e.g. Figer et al. 1999; Najarro et al. 2009), and one of the HII regions that we observed. The size of the field is ∼35′ × 20′ and the orientation is galactic north up, galactic east to the left.