Differential reddening maps for M9. Left: the recreated field of view using the 3D Bayestar 2019 reddening map (G. M. Green et al. 2019). Middle: the relative reddening map, as published by J. Alonso-García et al. (2012). Right: we degraded the resolution of the J. Alonso-García et al. (2012) map (AG12) to the same resolution as the Bayestar pixels, as can be seen here, then compared them to set the alternative absolute zero-point for the relative map.