Absolute magnitude of the turnoff point in the r band as a function of metalllicity and age for metal poor populations (green circles). The values in this diagram meet the age/metallicity relation for the Sgr dwarf galaxy from Layden & Sarajedini (2000). The isochrone used in this paper to derive distances to the Sgr stream is represented with a yellow star, and its maximum difference to the other brightness values in this range is ΔM =  ± 0.1mag.