ASTRONOMISCHE NACHRICHTEN, vol.326, no.5, pp.321-331, 2005 (SCI-Expanded)
We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g - r) and (r - i) for Sloan photometry. The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparcos.