High-resolution abundance analysis of two individual stars of the bulge globular cluster NGC 6553

A detailed abundance analysis of 2 giants of the metal-rich bulge globular cluster NGC 6553 was carried out using high resolution echelle spectra obta ined at the ESO 3.6m telescope. The temperature calibration of metal-rich cool giants needs high quality ph otometric data. We have obtained JK photometry at ESO and VI photometry wit h the Hubble Space Telescope for NGC 6553. The main purpose of this analysi s consists in the determination of elemental abundance ratios for this key bulge cluster, as a basis for the fundamental calibration of metal-rich pop ulations. The present analysis provides a metallicity [Fe/H] = -0.55+/-0.2 which, combined to overabundances relative to Fe of several elements, resul ts in an overall metallicity Z approximate to Z..