RGB photometric calibration of 15 million <i>Gaia</i> stars

Although a catalogue of synthetic RGB magnitudes, providing photometric data for sample 1346 bright stars, has been recently published, its usefulness is still limited due to the small number reference stars available, considering that they are distributed throughout whole celestial sphere, and fact restricted Johnson V < 6.6 mag. This work presents magnitudes ~15 million brighter than Gaia G = 18 mag, making use calibration between star corresponding high quality G, G_BP G_RP provided by EDR3. The exhibiting -0.5 - 2.0 aims predict within an error interval $\pm 0.1$ Since dominated nearby with slightly undersolar metallicity, systematic variations in predictions expected, as modelled help stellar atmosphere models. These deviations constrained mag when applying only scarcely affected interstellar extinction metallicity compatible median value sample. large sources available each region sky should guarantee high-quality calibrations.