Age and Metallicity Estimation of Globular Clusters from Stromgren   Photometry
  We present a new technique for the determination of age and metallicity in composite stellar populations using Stromgren filters. Using principal component (PC) analysis on multi-color models, we isolate the range of values necessary to uniquely determine age and metallicity effects. The technique presented herein can only be applied to old (tau > 3 Gyrs) stellar systems composed of simple stellar populations, such as globular clusters and elliptical galaxies. Calibration using new photometry of 40 globular clusters with spectroscopic [Fe/H] values and main sequence fitted ages links the PC values to the Str\"omgren colors for an accuracy of 0.2 dex in metallicity and 0.5 Gyrs in age. 
K. Rakos (UVienna) and J. Schombert (UOregon)