An Improved Metallicity Calibration with UBV Photometry
  We used the data of 701 stars covering the colour index interval
0.32<B-V<=1.16, with metallicities -1.76<=[Fe/H]<=+0.40 dex, which were taken
from PASTEL catalogue and estimated metallicity dependent guillotine factors
which provide a more accurate metallicity calibration. We reduced the
metallicities of 11 authors to the metallicities of Valenti & Fischer (2005),
thus obtained a homogeneous set of data which increased the accuracy of the
calibration, i.e. [Fe/H]=-14.316*delta^{2}_{0.6}-3.557*delta_{0.6}+0.105.
Comparison of the metallicity residuals, for two sets of data, based on the
metallicity dependent guillotine factors with the ones obtained via metal free
guillotine factors, shows that metallicities estimated by means of new
guillotine factors are more accurate than the other ones. This advantage can be
used in the metallicity gradient investigation of the Galactic components, i.e.
thin disc, thick disc and halo.
