The luminosity calibration of the uvby-$\beta$ photometry
  The ESA HIPPARCOS satellite has provided astrometry of unprecedented accuracy, allowing to reassess, improve and refine the pre-HIPPARCOS luminosity calibrations. We review the "classical" absolute magnitude calibrations with the Stroemgren-Crawford intermediate-band photometric system. A small zero point correction of about 2-4% seems necessary, as well as to refine the dependences on metallicity and projected rotational velocity. The need of a rigorous statistical treatment of the extremely precise HIPPARCOS to derive definite dependences of the luminosity on physical stellar parameters is emphasized. 
C. Jordi, X. Luri, E. Masana, J. Torra, F. Figueras, A. Domingo, A.E.   G\'omez, M.O. Mennessier