The Carina Dwarf Spheroidal Galaxy A Goldmine for Cosmology and Stellar Astrophysics

We present deep and precise multiband (U, B, V, I) optical data for the Carina dwarf spheroidal galaxy. Data were collected using three different ground-based telescopes (4-metre Blanco CTIO, MPG/ESO 2.2-metre, 1.5-metre CTIO) and cover the entire body of the galaxy. We discuss the reliability of the absolute photometric zero-point calibrations of images collected with large-format and mosaic CCD cameras. The typical precision for the B- , V- and I-bands is better than 0.01 mag. The U-band is a little worse. A preliminary comparison with scaled-solar and alpha-enhanced evolutionary predictions covering a broad range of ages and chemical compositions seems to support previous photometric evidence that both the old (12 Gyr) and the intermediate-age (4-6 Gyr) subpopulations show a limited spread in chemical composition. The use of the Carina galaxy field as a possible standard stellar field is outlined.