Aladin sky atlas (Bonnarel et al. 2000) views of 2MASS K (if both B_J and R_F were derived using 2MASS J and K, Skrutskie et al. 2006) or DSS2 red (Digital Sky Survey second generation, Lasker et al. 1996). All the six sources are in the southern hemisphere, so DSS2 red refers to red photographic plates from the Anglo-Australian Observatory F-band Second Epoch Survey (AAO-SES, Morgan et al. 1992), observed by the UK Schmidt Telescope, digitised by the Space Telescope Science Institute. The same plates were scanned by USNO-B1.0 or GSC23 to measure R_F. The six sources in Table 2 are indicated with a purple cross-hair (and green square). The blue arrow joins the target to a nearby brighter source, if suspected of contaminating its window. The red dots denote EDR3 sources. Top left: DR2 5305975869928712320; top right: DR2 5966712023814100736; middle left: DR2 4658865791827681536; middle right: DR2 5827538590793373696; bottom left: DR2 4092328917916154368; bottom right: DR2 5413575658354375040.