A method for reddening determination in the uvby photometric system (Mitteilung der Universitätssternwarte zu Jena Nr. 133)

A new method for reddening determination in the uvby system is described. Using a Quby parameter calibrated in terms of b–y it is possible to determine simultaneously luminosity, spectral type, reddening, and metallicity of a star. The colour excess rations for the uvby photometric system are given and also analytical functions for the ZAMS are presented.