Left: map of Hercules UFD showing the regions covered by the proprietary and archive LBT observations used in the present study. The solid lines display the contours of the most external LBC pointings of the dither pattern adopted during the April 2013 observations. The black points show the position of the photometric sources in the central and lateral fields observed by Sand et al. (2009). Symbol size is inversely proportional to the source r_Sloan magnitude. The solid and dashed ellipses mark the galaxy half-light and tidal radii, respectively. Right: footprints of the 5 × 5 dither pattern adopted during the April 2013 observations. The depth-of-coverage map for the r_Sloan -images is also shown in grey scale.